I did some reading in other places online about using the bare infinitive after the word "than," and while in a lot of cases it seems correct, I'm having a hard time telling whether it's correct in this particular case. Are both of the following valid?   1.) "I've got more to do than wait." 2.) "I've got more to do than to wait."   I also noticed that it seems like the first one sounds better if there's something after the word "wait":   3.) "I've got more to do than wait around for you."   Is this any more valid than the first sentence with the bare infinitive after "than"?

I was speaking to an English learner and said, “All you have to do is read a lot.” And they thought that sentence wasn’t grammatically correct because I dropped the word to between is and read.  They thought it should be “All you have to do is to read a lot.” That sounds weird to me.   How do I explain to them the reason you drop the to? Or am I incorrect and it really should have a to?


I am trying to upload excel sheet of 10000 records and 29 columns but giving me out of memory error, to solve this in increase memory size in eclipe.ini file but no use. I decrease columns upto 4 then it doesn't give me error. but for more columns error is coming . Here with attached screenshot of error

I am writing a client-side Swing application (graphical font designer) on Java 5. Recently, I am running into java.lang.OutOfMemoryError: Java heap space error because I am not being conservative on memory usage. The user can open unlimited number of files, and the program keeps the opened objects in the memory. After a quick research I found  and others saying on Windows machine the JVM defaults max heap size as 64MB.  Given this situation, how should I deal with this constraint?  I could increase the max heap size using command line option to java, but that would require figuring out available RAM and writing some launching program or script. Besides, increasing to some finite max does not ultimately get rid of the issue.  I could rewrite some of my code to persist objects to file system frequently (using database is the same thing) to free up the memory. It could work, but it's probably a lot work too.  If you could point me to details of above ideas or some alternatives like automatic virtual memory, extending heap size dynamically, that will be great.


Whenever I use the command sudo apt-get update I get the following error:  W: GPG error: http://archive.ubuntu.com trusty Release: The following signatures were invalid: BADSIG 40976EAF437D05B5 Ubuntu Archive Automatic Signing Key <ftpmaster@ubuntu.com>   Please help me I am very new to all this.

I frequently cross this issue, and always have to google for an answer. Does anyone have a permanent fix for BADSIG errors from apt-get?     W: GPG error:    lucid   Release: The following signatures were   invalid: BADSIG 54422A4B98AB5139   Oracle Corporation (VirtualBox archive   signing key)


Any help would be appreciated. Thanks in advance :p Thanks to this tutorial  I could follow this tutorial until the render time but when I rendered shader reflected circle, just a blue colored plane showed up: without any wave texture. I can see what I want in the material preview but in the render the wave texture doesn't appear..

When I try to render a wave, it keeps being rendered in extremely low quality. I'm not sure exactly which setting is causing this, but increasing the renderand viewport sampling don't seem to help.


I've  been able to successfully use ftpwebrequest for uploading and downloading files via standard ftp protocol.  I thought I would be able to use .EnableSSL = True but I still can't connect to the sFTP site.  Research has indicated that .NET libraries don't natively support sFTP - can anyone provide some insight on transferring a file via sFTP?  Thanks!

Can anyone recommend a good SFTP library to use?  Right now I'm looking at products such as SecureBlackbox, IPWorks SSH, WodSFTP, and Rebex SFTP.  However, I have never used any SFTP library before so I'm not sure what I'm looking for.  If anyone has used these before, is there any reason why I should go with product "X" over "Y"?


I have somewhat of a general question, and I hope this is the right place to ask.    We currently have 11 (9 Red Hat/2 Centos) servers, which have been purchased at different times over the last 5 years, and although they all have Linux OS, there are hardware differences between them, simply because they were bought at different times.  However, we need a core set of bioinformatics software installed on all of the machines to allow users to have the same environment.  In the past we have used a shared mounted drive, but we have run into problems when software does not work on a given machine because not all necessary libraries were installed, etc.    Long story short, I’m looking for tips and advice as to the best approach to this problem.  Do you think working on a shared drive and troubleshooting issue as they occur is the best path, or is there an improved method I’m not privy to (software/ theoretical).  Ultimately I feel that trying to maintain each machine independently has to be the most painful method.

I work at the university. In my institute we have six computer laboratories used for teaching. Each lab has almost 20 computers, which gives over 100 machines total. Computers have either Windows XP or Windows 7 Eneterprise operating system. We use Symantec Ghost to manage all the computers. Each computer has a Ghost client installed, which allows to control computers over network. Every six months we restore a master image on one of the computers in a lab, update that image and distribute it over the network to all computers in a laboratory. Thanks to Ghost client this is done automatically with just a few clicks.  Recently I suggested that it would be good to have Linux installed in the laboratories. The administrators were concerned that we would not be able to manage that many computers if each would have to be updated manually. The question is: how to manage such a huge network of Linux machines in an automated way?  To make the description of our network more complete I'll add that all students have their accounts (about few thousand users) on a central server. These are accessed via LDAP. To use a computer in laboratory each student has to log in using his own account.


How to write global keyboard hook in Ubuntu (Linux) (like Hook for Windows)  In C/C++ or Python

What would be the best approach to install a keyboard hook on Linux (X-windows) in order to trigger some application when some key-combo is pressed?? Is there a way to do this regardless of which window manager is running? The idea is to have an application being called ( or brought to foreground ) when some key is pressed in a way similar that Google Desktop does to Ctrl-Ctrl.


Find the sum $$\sum _{n=1}^{\infty} {1\over n^2}$$ elementary! I know the result is $\pi^2/6$, but I wonder if there is an elementary approach i.e. with a high school knowledge to this sum.

As I have heard people did not trust Euler when he first discovered the formula (solution of the ) $$\zeta(2)=\sum_{k=1}^\infty \frac{1}{k^2}=\frac{\pi^2}{6}.$$ However, Euler was Euler and he gave other proofs.   I believe many of you know some nice proofs of this, can you please share it with us?


I'm having trouble adapating to the behaviour of PowerShell tab completion from bash tab completion and wondering if there is a way to change it.  In PowerShell when I press tab it expands to the first available match. You can press Tab again to get to the next result. In bash it expands only as far as the common match. If you press tab again a list of available matches are shown but the command line is not further modified.  The problem I have in PowerShell is that if there are many matches I don't want to tab through them all; it takes too long and I often miss the one I want. I want like in bash where I can keep typing from the common prefix to narrow down the selection.  Is there someway to change this behaviour in PowerShell?

Under Windows, using PowerShell, is it possible to make the filename suggestion (using the Tab key) work like with bash under Linux?  Let's assume a directory contains 3 directories: example1, example and examination.  On Windows (by default), if you type cd ex and Tab, it will auto-suggest cd .\examination. Subsequent uses of Tab will rotate the suggestion between example1, example and examination.  Using bash (typically under Linux), if you type cd ex and Tab, it will auto-complete until the character where the filenames start to differ: cd exam. Another use of Tab then suggests which directories are available:  $ cd exam examination/ example1/    example2/   Then, if you type p and Tab, it will auto-complete to example, and so on (here, offering a choice between example1 and example2).  Is there a way to make the filename suggestion work in a tree-like search like this, instead of rotating through the names?  (I'm mainly interested in file names. Bash can also refine this selection based on the file type, for example only directories for cd, which would be good, but having the file name selection itself would be enough.)


I have a problem with ajax form submission. My problem is whenever I click submi it redirect me to a new page and show me the responses there. here is my django view @csrf_exempt def my_view(request):     if request.is_ajax and request.method == "POST":         # do something and if successfully         return JsonResponse({'success': True}, status=200)          # if not success         return JsonResponse({'fail': True}, status=400)      # other thingss  my template <div id="form-div">     <form action="{% url 'my_view' %}" method="POST" id="my-form">         # some fields ..         <button type="submit">submit</button>     </form> </div>  ajax $("#my-form").submit(function (e) {     e.preventDefault();     $.ajax({         type: "POST",         url: my_url,         data: {some datas},         success: function (response) {             # some jquery code to update DOM         },         error: function (response) {             # some jquery code to update DOM         }     }) })  Now the code above that i showed you works fine for me but the problem comes if I append the form on event like this. <button id="my-btn">my btn</button>  $("#my-btn).click(function(e) {     e.preventDefault();          $(#form-div).append(     "     <form action="{% url 'my_view' %}" method="POST" id="my-form">         # some fields ..         <button type="submit">submit</button>     </form>     "     ); })  after I clicked the button and inspected the form it showed the exact same as my original form but if i do the post request it will redirect me the other page rather than execute the query code I defined. What is the problem here?

I have a bit of code where I am looping through all the select boxes on a page and binding a .hover event to them to do a bit of twiddling with their width on mouse on/off.  This happens on page ready and works just fine.  The problem I have is that any select boxes I add via Ajax or DOM after the initial loop won't have the event bound.  I have found this plugin (), but before I add another 5k to my pages with a plugin, I want to see if anyone knows a way to do this, either with jQuery directly or by another option.


We may also ask: Is the assumption of continuity of spacetime required by Lorentz Invariance?

It is usually said that existence of discrete spacetime violates Lorentz symmetry. What quantity is used to quantify such violation? I mean could someone points a reference for a derivation that shows such analysis.  My other question is: if Lorentz symmetry is violated, does that imply space-time is discrete? or not necessarily?)


I am checking whether the specified word can be formed on this boggle board with the canForm method. The board has a graph field which indicates adjacent tiles. I do a DFS and set answer to true if the word can be formed.  I understand why the code as it is below doesn't work: answer is a primitive, its value is copied at every recursion and the initial answer (in the public method) stays false.  If I change boolean answer to Set<String> answer = new HashSet<>() for instance, pass the reference to the set in recursion, eventually add the successfully formed word and test for emptiness in the end, it works.  But why does it not work if I simply declare Boolean answer = new Boolean(false) and pass this container? It passes the reference to the object all right, but it mysteriously changes the reference at assignment answer = true (as seen through the debugger), and the initial answer isn't reset. I don't understand.   public boolean canForm(String word) {      boolean answer = false;     int n = M * N;     char initial = word.charAt(0);      // for each tile that is the first letter of word     for (int u = 0; u < n; u++) {         char c = getLetter(u / N, u % N);         if (c == initial) {             boolean[] marked = new boolean[n];             marked[u] = true;             canForm(u, word, 1, marked, answer);         }     }      return !answer; }  private void canForm(int u, String word, int d, boolean[] marked, boolean answer) {      if (word.length() == d) {         answer = true;         return;     }      for (int v : graph.adj(u)) {         char c = getLetter(v / N, v % N);         if (c == word.charAt(d) && !marked[v]) {             marked[v] = true;             canForm(v, word, d + 1, marked, answer);         }     } }

I always thought Java uses pass-by-reference. However, I've seen a couple of blog posts (for example, ) that claim that it isn't (the blog post says that Java uses pass-by-value). I don't think I understand the distinction they're making. What is the explanation?


Suppose I have a number $x$ such that, $$ x \equiv 31^{29}  \text{ (mod 57)} $$ How can I find $x$ using properties of modular arithmetic. Will it involve a special theorem?

I've read about Fermat's little theorem and generally how congruence works. But I can't figure out how to work out these two:   $13^{100} \bmod 7$ $7^{100} \bmod 13$   I've also heard of this formula:  $$a \equiv b\pmod n \Rightarrow a^k \equiv b^k \pmod n $$  But I don't see how exactly to use that here, because from $13^1 \bmod 7$ I get 6, and $13^2 \bmod 7$ is 1. I'm unclear as to which one to raise to the kth power here (I'm assuming k = 100?)  Any hints or pointers in the right direction would be great.


I was reading a book on English grammar and it stated that the object complement may also be an adjective. In the sentence "Roger called George heartless", Roger was the subject, called was the verb, George was the direct object and heartless is the object complement. But heartless is what receives the verb, and George should be the indirect object. If we change "heartless" to "a moron", we see that moron becomes the direct object while George becomes the indirect object?  Is there something wrong with my reasoning?  Edit: So what I meant when I said heartless is what receives the verb, is that with direct objects, the subject is performing the verb and the verb is performed on the direct object. For example, "You broke the window!". You is the subject, broke is the verb and window is the direct object. In this sentence, window 'receives' the verb.

Reading English Grammar (HarperCollins College Outline, published by HarperResource, an imprint of HarperCollinsPublishers) I found a chapter (Sentence Basics) that explains that in English there are different sentence patterns; in particular   Subject, verb, direct object, object complement Subject, verb, indirect object, direct object   The chapter reports the following example for the patterns:     Alice called Charles Professor Miller.   Alice gave Charles the rabbit.   What is the difference between the two kind of sentences? What is the difference between the object complement in the first case, and the indirect object in the second case?  PS: The question, which could appear silly, comes from the fact in my first language there is only the object complement.


I need perl script to connect to database, but don't want the password in plain text.   any suggestion how to hide the password in plain text would be great.

When a PHP application makes a database connection it of course generally needs to pass a login and password. If I'm using a single, minimum-permission login for my application, then the PHP needs to know that login and password somewhere. What is the best way to secure that password? It seems like just writing it in the PHP code isn't a good idea.


As long as a CPU's temperature stays below the manufacture-specified maximum, does a CPU's average temperature affect its lifespan?  For example, my laptop's maximum CPU temperature as specified by Intel is 100(C). If I run it at 90(C) for a period of time vs. running it at 40(C) for the same period of time, will there be a difference in how much of the processor's life that has been used up?  Is there credible scientific research on this subject?  My reason for asking this is that I am trying to determine whether to increase my default fan speeds in order to lower the temperature that my CPU idles and works under light load such as typing this question.  P.S: even though I've tagged this 'overclocking', this question is not concerned with the effects of overvolting a CPU.

I often do 3D rendering in the background which consumes 100% of the CPU (I lower the priority of the process so that it does not hinder any tasks I am working on).  My concern/question is whether it is okay to run a computer/laptop with a 100% CPU load constantly.  Could this reduce the lifespan of the system?


Interaction between a nucleus and electrons is in gravity(not considering) and electrostatics. Due to electrostatics nucleus attracts electrons. The force that describes this process is  $$F=k\dfrac{q_1 \, q_2}{r^2}$$  What I want to say, is that, the force is "smooth" depending on distance: it doesn't looks like a sinusoidal, I mean there are no strongly-marked values.  Why, then atom has a the straight discrete energy levels?

I have seen similar posts, but I haven't seen what seems to be a clear and direct answer.  Why do only a certain number of electrons occupy each shell? Why are the shells arranged in certain distances from the nucleus? Why don't electrons just collapse into the nucleus or fly away?  It seems there are lots of equations and theories that describe HOW electrons behave (pauli exclusion principle), predictions about WHERE they may be located (Schrödinger equation, uncertainty principle), etc. But hard to find the WHY and/or causality behind these descriptive properties.  What is it about the nucleus and the electrons that causes them to attract/repel in the form of these shells at regular intervals and numbers of electrons per shell?  Please be patient with me, new to this forum and just an amateur fan of physics.


Consider estimating the binomial success parameter using glm.  glm(cbind(3,10)~1, family = binomial()) # 3 successes, 10 failures   The table is  Coefficients:             Estimate Std. Error z value Pr(>|z|)   (Intercept)  -1.2040     0.6583  -1.829   0.0674 . --- Signif. codes:  0 ‘***’ 0.001 ‘**’ 0.01 ‘*’ 0.05 ‘.’ 0.1 ‘ ’ 1  (Dispersion parameter for binomial family taken to be 1)      Null deviance:  0.0000e+00  on 0  degrees of freedom Residual deviance: -3.2646e-24  on 0  degrees of freedom AIC: 4.7333  Number of Fisher Scoring iterations: 3   Note that the model fails to reject the null at the 5% significance level.  However, if I then estimate the confidence interval for this model I get       2.5 %     97.5 %  0.06302025 0.49511505   Note now that the null value is outside the confidence interval, and we should reject the null hypothesis.  Some documentation reading reveals there is another method called confint.default based on asymptotic normality which returns the following confidence interval                  2.5 %    97.5 % (Intercept) 0.07626731 0.5215448   Does R use asymptotic normality in the glm coefficient table but profile likelihood when I call confint?  What else may explain this discrepancy?

Dear everyone - I've noticed something strange that I can't explain, can you? In summary: the manual approach to calculating a confidence interval in a logistic regression model, and the R function confint() give different results.  I've been going through Hosmer & Lemeshow's Applied logistic regression (2nd edition).  In the 3rd chapter there is an example of calculating the odds ratio and 95% confidence interval.  Using R, I can easily reproduce the model:  Call: glm(formula = dataset$CHD ~ as.factor(dataset$dich.age), family = "binomial")  Deviance Residuals:     Min      1Q  Median      3Q     Max   -1.734  -0.847  -0.847   0.709   1.549    Coefficients:                              Estimate Std. Error z value Pr(>|z|)     (Intercept)                   -0.8408     0.2551  -3.296  0.00098 *** as.factor(dataset$dich.age)1   2.0935     0.5285   3.961 7.46e-05 *** --- Signif. codes:  0 ‘***’ 0.001 ‘**’ 0.01 ‘*’ 0.05 ‘.’ 0.1 ‘ ’ 1   (Dispersion parameter for binomial family taken to be 1)      Null deviance: 136.66  on 99  degrees of freedom Residual deviance: 117.96  on 98  degrees of freedom AIC: 121.96  Number of Fisher Scoring iterations: 4   However, when I calculate the confidence intervals of the parameters, I get a different interval to the one given in the text:  > exp(confint(model)) Waiting for profiling to be done...                                  2.5 %     97.5 % (Intercept)                  0.2566283  0.7013384 as.factor(dataset$dich.age)1 3.0293727 24.7013080   Hosmer & Lemeshow suggest the following formula:  $$ e^{[\hat\beta_1\pm z_{1-\alpha/2}\times\hat{\text{SE}}(\hat\beta_1)]} $$   and they calculate the confidence interval for as.factor(dataset$dich.age)1 to be (2.9, 22.9).  This seems straightforward to do in R:  # upper CI for beta exp(summary(model)$coefficients[2,1]+1.96*summary(model)$coefficients[2,2]) # lower CI for beta exp(summary(model)$coefficients[2,1]-1.96*summary(model)$coefficients[2,2])   gives the same answer as the book.  However, any thoughts on why confint() seems to give different results?  I've seen lots of examples of people using confint().


I have a database of around 126K entries, It has many entries having duplicate emails. I want to delete all the entries with duplicate ones and just the keep the one that was created earliest.   I tried using the following query but it takes forever and maxes out my server bandwidth.   Can anyone help?   DELETE n1 FROM table n1, table n2 WHERE n1.ID > n2.ID AND n1.email = n2.email     Database Specifications   PhpMyAdmin Version information: 3.5.3 Server: Localhost via UNIX socket Software: MySQL Software version: 5.0.67-community - MySQL Community Edition (GPL) Protocol version: 10 Server charset: UTF-8 Unicode (utf8)

What is the best way to remove duplicate rows from a fairly large SQL Server table (i.e. 300,000+ rows)?  The rows, of course, will not be perfect duplicates because of the existence of the RowID identity field.  MyTable  RowID int not null identity(1,1) primary key, Col1 varchar(20) not null, Col2 varchar(2048) not null, Col3 tinyint not null


hope all is going well for you!  I'm having an issue where the eyes and teeth of a MakeHuman model do not quite work properly with a Rigify rig.   Simply put, I have no idea how to fix this. If anyone can provide some insight concerning this, I would greatly appreciate it. Also if anyone needs to poke around in the blend file itself,  is a link.  If any other details are needed, just let me know!  Thanks, and take care. =-)

So I'm trying to weight paint but can't seem to get my teeth and beard on the character to move with his head on two different bones, I have tried to move the head then weight paint it so that it gets moved into position as I paint but that doesn't work because it just stops getting closer to the head... so if someone could help using like team viewer or something that would help me a ton.   newest image:


I was playing Skyrim and since I have the Dragonborn DLC, I went to Soltheim and told Serana to wait or something, and now I can't find her! I'm using a ps3 and I can't use console commands, please help. I've already tried waiting but it doesn't help, and it wont let me recruit any other followers.

I had parked my follower at an inn with a bunch of valuable items that I didn't want to carry. I guess I have been out a bit too long as this message appears:      Your follower tires of waiting and leaves.    There have been other situations where my follower has mysteriously disappeared as well.  How can I find my follower when they get up and leave or disappear into thin air?


I have Bulgaria-Turkey dual citizenship with different names (not even a word is matching in surname or name, totally different, only birthdays are matching in two passports basically). I do live in Singapore (I have a residency visa w my Turkish passport & name). I have a coming trip to Europe, and we will be visiting Germany, France and Portugal, for about 2 weeks.  Since I have Bulgarian passport (EU citizen), I have freedom of travel in EU countries.  My questions are: 1. Under which name I should book my tickets? Or should I book w different names for internal EU layover flights? Or it doesn't matter?   My plan is initially:   Book ticket w (home country (SG)), Turkish passport (since I have SG residency). Airline check-in, show them my Bulgarian passport (EU). At Immigration, show Turkish (TR) passport w Residency when leave. Arrive Germany, show BG passport at immigration. Flying to France, at check-in,  show Bulgarian passport (but for name mismatch, I show TR passport, or I book my ticket with BG passport for internal EU flights is better?) At immigration, show BG passport (my worry is at immigration if they wanna check my ticket & BG passport, they will see mismatch names, and I need to explain them dual citizenship).  Arrive France, show BG passport at immigration. Flying to Portugal, at check-in, show BG passport (again for name mismatch, I show TR passport, or I book my ticket w BG passport for internal EU flights? basically the same thing as #5) At immigration, show BG passport (Again, same concerns as #6, and may need to explain them dual citizenship). Arrive Portugal, show BG passport at immigration. Flying back to SG, at check-in, show TR passport since i have a residency visa. (this time name is matching) At immigration show BG passport (Again, same concerns as #6, ticket and name in BG passport not matching) Arrive SG, show TR passport at immigration.   Please let me know if my plan sounds correct.   In summary,    A) should I follow same name booking ( in this case home country (SG) w TR passport) for all flights?   B) or should I book EU flights w BG passport separately?  C) or should I just book all flights w BG passport since they are the majority of flights in this case?   Besides above questions, If you have any other suggestions, I would like to hear them as well. Thanks in advance. Cheers

I am a citizen of two different countries, and have two passports.  How should I use my passports when traveling?


$R$ is a ring, containing more than one element, such that   $\forall 0\ne a\in R \exists ! b\in R; aba=a$.  Here's what I did in the very first place: $(aba)a^{-1}=aa^-1 \text{ and } a^{-1}(aba)=a^{-1}a\Longrightarrow \left\{ \begin{array}{rl} ab=1 & \forall0\ne a\in R \exists !b\in R \\ ba=1 & \forall0\ne a\in R \exists !b\in R \end{array} \right.$ Therefore, since $ab\in R\Longrightarrow 1\in R$. So $R$ is a ring with identity.   But then I realized, how one can say $aa^{-1}=1$ when one doesn't know whether $R$ is a ring with identity.

Somebody can to help me in such exercices:     (1) A ring R such that $a^2 = a$ for all $a\in R$ is called a Boolean ring. Prove that every    Boolean ring R is commutative and $a + a = 0$ for all $a \in R$.       (2) Let R be a ring with more than one element such that for each nonzero $a\in R$ there is a unique $b \in R$ such that $aba = a$. Prove:            (a) R has no zero divisors.           (b) $bab = b$.           (c) R has an identity.           (d) R is a division ring.       My greatest difficulty in the question 2 is to prove that R has no zero divisors.   Thanks!


As 1 epoch means each data point has gone through the algorithm once and made changes in weighted values accordingly . So , why there is a need to process same data again and again ? How does it decreases loss function ?

I have found many answers to the question of what an epoch is, but none to this:  Why do we use multiple epochs when training a neural net? How does this not lead to overfitting?  From my understanding 2 epochs means we training with each data point using SGD at least twice.   Why do we not do this when training regression models?


A multiple choice exam has 175 questions.  Each question has 4 possible answers.  Only 1 answer out of the 4 possible answers is correct.  The pass rate for the exam is 70% (123 questions must be answered correctly).  We know for a fact that 100 questions were answered correctly.    Questions: What is the probability of passing the exam, if one were to guess on the remaining 75 questions? That is, pick at random one of the 4 answers for each of the 75 questions.

A multiple choice exam has 175 questions.  Each question has 4 possible answers.  Only 1 answer out of the 4 possible answers is correct.  The pass rate for the exam is 70% (123 questions must be answered correctly).  We know 100 questions were answered correctly.  What is the probability of passing the exam, if one were to guess on the remaining 75 questions?


what does including but not limited to mean here? And what means to post calls for artists?     This space collects any kinds of open-call opportunities for artists   and arts professionals, including but not limited to residency   programs, workshops, exhibition/ festival projects. Please feel free   to post calls.

You will not be permitted to bring any personal items to the test centre, including but not limited to wrist-watch, cellphones, calculators, etc.    I think it means a candidate will not be permitted to bring any items. Is this right or wrong? Please explain with some examples.


If I start a terminal (any terminal, for example urxvt) like urxvt -e sleep 5, then a new terminal is launched but after 5 seconds the terminal closes, because the sleep program has ended. How can I start a terminal with a program on the command line, but have the terminal stay alive after that process has ended?  In practice, what I'd actually like to do is urxvt -e tmux new-session top, which opens urxvt with a tmux session that is running top. But when I press q, top ends which also causes tmux and urxvt to end as well. I'd like when I exit top for me to be taken to a shell within tmux.

In my tmux.conf file I have it configured to open windows, name them, setup panes etc.. etc..  However one issue I have is that if one of the panes launches a command, let's say ls, then the pane closes itself after the command completes (instantly). Is there any way to prevent this behavior? Or have it drop to a normal shell after a command completes?  I am assuming that I need to start a shell -> execute command when the pane launches, but I'll be damned if I can figure out how. I have googled a bit for this problem but have come up short.


Despite trying all the fixes on this board and elsewhere, I STILL get the same break running   $ /usr/bin/convert D1.JPG P1.pdf   namely:  unable to open image `P1.pdf': No such file or directory @ error/blob.c/OpenBlob/2701. convert-im6.q16: missing an image filename `20' @ error/convert.c/ConvertImageCommand/3255.   This bug started in U18.04 initial release and still persists on latest U18.04 refresh - it has never been fixed.

convert /home/bill/TempScan/*.png  myfile.pdf   gives error message:  convert-im6.q16: not authorized `myfile.pdf' @ error/constitute.c/WriteImage/1037.   Any help would be appreciated!


In Serge Lang: Algebra it is stated on page 69 that for a group $G$ that, if for $x,y,z\in G$ $y=[x,y]:=xyx^{-1}y^{-1}, z=[y,z], x=[z,x]$ is satisfied, we have $x=y=z=e$. I see that $y=[x,y]$ directly implies $y=x^{-n}y^{2^n}x^n$ for $n>0$, but I need a hint why it is true for $n=0$.  Edit: As pointed out in the comments: the relation should be $y^n=x^{-1}y^{2^n}x$.

Problem: Show that the group given by the presentation $$\langle x,y,z  \mid xyx^{-1}y^{-2}\, , \, yzy^{-1}z^{-2}\, , \, zxz^{-1}x^{-2} \rangle $$ is equivalent to the trivial group.   I have tried all sorts of manners to try to show that the relations given by the presentation above imply that $x=y=z=e$. However, I am stuck and would appreciate any hints as to how I should move forward.


I have a website running on Django, Python. I'm using django pagination so that users can click next & see further content.  For example, my website is example.com, so when user requests new page it takes them to example.com/?page=2 & example.com/?page=3 & so on . . .  But, the problem is that google has indexed all the paginated webpages (?page=2, ?page=3, etc.) & also showing the duplicate title error inside console.  So, I want to remove all the paginated webpages accept example.com from search results. I tried adding canonical tag <link rel="canonical" href="https://www.example.com/" /> & then tried removing example.com/?page=2 page using console remover, but my request was denied & the page is still there.  I was thinking about a solution, which is to add this code,  {% if not request.get_full_path is '/example.com/' %}     <meta name="robots" content="noindex, follow"> {% endif %}   But, this logic is not working as it should. The if statement is not working properly.  How we solve this problem? Thank You . . .

I have used so many things like url removal request and deleted the pages etc., but still the errors are shown in my webmaster tools.  How can I remove the urls completely from Google?


I installed Ubuntu. Now I get:   "fatal err. not os detected.   I cant boot from dvd either  What can I do?

I installed Windows 7, which ate Ubuntu's boot file. When starting up the computer, it now goes straight to Windows, without giving me the option of booting Ubuntu.   How can I get Ubuntu back?


What is the best method utilizing javascript to parse this JSON response:    {     "records":[{          "id":"recV4gf3nPUzO980w",          "fields":{             "truck name":"Darla's dumpling cart",             "address":"150 W 57th St, New York, NY"          },          "createdTime":"2018-04-27T22:48:13.000Z"     }] }    So that only the "fields" data is returned, This is a representation of only one record in records and I need to create obj.records.fields where all fields are presented as an array.

Given a string of JSON data, how can I safely turn that string into a JavaScript object?  Obviously I can do this unsafely with something like:  var obj = eval("(" + json + ')');   but that leaves me vulnerable to the JSON string containing other code, which it seems very dangerous to simply eval.


When trying to install WINE (sudo apt-get install wine) I get the following error:  Some packages could not be installed. This may mean that you have requested an impossible situation or if you are using the unstable distribution that some required packages have not yet been created or been moved out of Incoming. The following information may help to resolve the situation:  The following packages have unmet dependencies:  wine : Depends: wine1.5 but it is not going to be installed E: Unable to correct problems, you have held broken packages.   Google does tell me that apparently this has something to to with ia32-libs, but I cannot find out how to do to fix the dependencies or if I need to (manually?) install something else.  I have added ppa:ubuntu-wine/ppa to my repositories.  sudo apt-get install wine1.5gives me  The following packages have unmet dependencies:  wine1.5 : Depends: wine1.5-i386 (= 1.5.4-0ubuntu1~ppa1~precise1+pulse17)   sudo apt-get install wine1.5-i386gives me  The following packages have unmet dependencies:  wine1.5-i386:i386 : Depends: libgphoto2-2:i386 (>= 2.4.10.1) but it is not going to be installed                      Depends: libgphoto2-port0:i386 (>= 2.4.10.1) but it is not going to be installed                      Recommends: gettext:i386 but it is not going to be installed                      Recommends: libsane:i386 but it is not going to be installed   Any help would be appreciated. Thanks.

Occasionally, when I'm installing stuff, I get an error like the following:  Some packages could not be installed. This may mean that you have requested an impossible situation or if you are using the unstable distribution that some required packages have not yet been created or been moved out of Incoming. The following information may help to resolve the situation:  The following packages have unmet dependencies:  package1 : Depends: package2 (>= 1.8) but 1.7.5-1ubuntu1 is to be installed E: Unable to correct problems, you have held broken packages.   How can I resolve this?


Although I'm a native English speaker, I'm confused by the above sentence found on the page . I've been debating with myself throughout the day whether I should interpret it as meaning before January 1st, 2016, or sometime during the day of January 1st 2016.

I have read the Rules of a competition. The text of the Rules include a sentence as follows:     As per stated in the Rules the entrants will be notified by May 30th 2010.   Does the sentence above mean that May 30th is included in the term of notification or not?


I'm programming a window where the user has to type a date on a input field but I don't know how to check if the day or month are coherent or not (like day between 1-31 and month between 1-12)      String string = "26/03/2017";     DateFormat format = new SimpleDateFormat("dd/MM/yyyy") ;      try {         Date date = format.parse(string);     } catch (ParseException e) {         e.printStackTrace();     }   This is the piece of code where I'm formatting the Date, but I have no idea to check what I said before.

I find it curious that the most obvious way to create Date objects in Java has been deprecated and appears to have been "substituted" with a not so obvious to use lenient calendar.  How do you check that a date, given as a combination of day, month, and year, is a valid date?  For instance, 2008-02-31 (as in yyyy-mm-dd) would be an invalid date.


Volume 4 of Charles Burney,  (1776) contains this sentence:     And while it [Rousseau's Lettre sur la Musique Françoise] was read by all the rest of Europe as an excellent piece of musical criticism, full of new ideas and views concerning dramatic Music, it was held in execration by the adherents to the ancient style of opera Music, and has been lately called "a wretched performance, dictated by spleen, bad taste, want of judgment, and inconsistence," by a writer [M. de la Borde] who, on some occasions, seems to know better, and to have ideas of good Music, more worthy of a master of harmony and the present state of the art in every part of Europe.   My questions are: How, when and where did the phrase 'state of the art' originate?

I recently saw the etymology of the word technology and it comes from Greek thchni meaning art and logos which means word, reasoning, and stuff like that. So I reckon technology means doing something such that people consider it as a work of art. On the other hand, we sometimes see state-of-the-art which is used as adjective, or adverb in some contexts.   My question is, are they equal in meaning? Can we use them interchangeably? Is state-of-the-art a literal translation of technology?


I tried the following code with sprintf, but it crashes in some cases and works fine in the other. Could anyone explain it to me?  #include <stdio.h> #include <stdlib.h> int main() {        //char *s = malloc(20); //works fine        //char *s = "";         //does not work, no matter what the initial value is        char s[20];       //works fine        sprintf(s, "%s", "hello world");        printf("%s",s);        return 0; }

The following code receives seg fault on line 2:  char *str = "string"; str[0] = 'z';  // could be also written as *str = 'z' printf("%s\n", str);   While this works perfectly well:  char str[] = "string"; str[0] = 'z'; printf("%s\n", str);   Tested with MSVC and GCC.


I would like to be able to embed a chart/graph of attributes for each feature within a webmap. I've had a look around and haven't found anything definitive on the  pages of how to achieve this.

I would like to make graphs, pie charts, etc based on fields in my table within my infowindows. Is there a way to accomplish this?


if X and Y are independent Random variable then what is the variance of XY?

We know the answer for two independent variables: $$ {\rm Var}(XY) = E(X^2Y^2) − (E(XY))^2={\rm Var}(X){\rm Var}(Y)+{\rm Var}(X)(E(Y))^2+{\rm Var}(Y)(E(X))^2$$  However, if we take the product of more than two variables, ${\rm Var}(X_1X_2 \cdots X_n)$, what would the answer be in terms of variances and expected values of each variable?


I am sure this is fairly simple, but I am just not getting it.   I am not sure how to show that $\liminf_n→_∞ A_n \ $ ⊆ $\limsup_n→_∞ A_n \ $  I guess I am not understanding lim inf and lim sup properly.

I am stuck on proofs with subsequences. I do not really have a strategy or starting point with subsequences.   NOTE: subsequential limits are limits of subsequences  Prove: $a_n$ is bounded $\implies \liminf a_n \leq \limsup a_n$   Proof:  Let $a_n$ be a bounded sequence. That is, $\forall_n(a_n \leq A)$.  If $a_n$ converges then $\liminf a_n = \lim a_n = \limsup a_n$ and we are done.  Otherwise $a_n$ has a set of subsequential limits we need to show $\liminf a_n \leq \limsup a_n$:  This is where I am stuck...


Let $X_1,X_2,...$ denote iid random variables such that $X_1$ is continuously distributed with density $p(x)$ and distribution function $F(x)$ where $F(0) = 0, F(x) > 0$ for all $x > 0$, and $p(0) > 0$. Let   $\hspace{15mm}Y = n\cdot  \min \{X_1,...,X_n\}$.  Then there exists a random variable Y such that:   $\hspace{15mm} Y_n \xrightarrow{D}Y$ as $n \xrightarrow{} \infty$.  What is the distribution function of $Y$?  I'm not sure how to proceed with this question. Any insight would be much appreciated.

Let $Z_i,Z_2,\ldots$ be IID Random Variables with density $f$. Suppose that $P(Z_i>0)=1$ and that $\lambda=\lim_{x \to 0+} f(x)>0$. How can I show that $X_n=n \times \min\{Z_i\}$ has a limiting exponential distribution with mean$1/\lambda$?  I know that the CDF of the first order Statistic is for $t>0$  $$F_{min \{ Z_i \}} (t)= 1- \left[ 1-F(t) \right]^{n}$$  Convergence in distribution requires that $F_n (t) \to F(t)$ for some distribution function $F$ but I cannot quite take the limit of the above, with $t$ replaced by $x/n$, as the distribution is not known. I guess I have to insert the second piece of information somewhere but I do not recognise where.  Could you please give me a hint or two?  Thank you.


How can we prove that cardinality of set of all real numbers $\mathbb{R}$ and $\mathbb{R}^n$ is equal for every $n$ in the set of all natural numbers?

I am working on this exercise for an introductory Real Analysis course:     Show that |$\mathbb{R}$| = |$\mathbb{R}^2$|.   I know that $\mathbb{R}$ is uncountable. I also know that two sets $A$ and $B$ have the same cardinality if there is a bijection from $A$ onto $B$. So if I show that there exists a bijection from $\mathbb{R}$ onto $\mathbb{R}^2$ then I beleive that shows that |$\mathbb{R}$| = |$\mathbb{R}^2$|.   Let $x_i \in \mathbb{R}$, where each $x_i$ is expressed as an infinite decimal, written as $x_i = x_{i0}.x_{i1}x_{i2}x_{i3}...,$. Each $x_{i0}$ is an integer, and $x_{ik} \in \left \{ 0,1,2, 3, 4, 5, 6, 7, 8, 9 \right \}$. Then, let  $$f(x_i)=(x_{i0}.x_{i1}x_{i3}x_{i5}... ,x_{i0}.x_{i2}x_{i4}x_{i6}...)$$  What should I do to show that $f: \mathbb{R} \to \mathbb{R}^2$ is an injective function? Any suggestions or help with the question would be appreciated.


My LUbuntu 18.04's lxpanel is not working. Which command can I run to   adjust brightness of my screen? Thanks.

To work around  (changing LCD brightness via hotkeys impossible), I'd like to have one command line query for increasing and one for reducing the brightness of my LCD. I could then map a hotkey to each one of this queries.  The problem is: I don't know how to increase and reduce the LCD brightness on the command line. Do you?


The following conditional is not working; when I use \def\Assignment{Examples}, the file  \input{\code/Assessment/#1/#2/#2} is not read.   \ifx\Assignment Examples  \qformat{\underline{\textbf{#5 \thequestion } }}          \loop       \input{\code/Assessment/#1/#2/#2}     \addtocounter{int}{1}\ifnum\value{int}<#4  \repeat   \else     \if\Assignment Quiz   \scriptsize{\textbf{This assessment instrument assesses the following Course Learning Outcomes (CLO) and grading scheme: }} \vspace{-0.25em} \qformat{\underline{\textbf{#5 \thequestion } }\droptotalpoints}         \loop        \input{\code/Assessment/#1/#2/CLO} \input{\code/Assessment/#1/#2/#2}     \addtocounter{int}{1}\ifnum\value{int}<#4  \repeat   \fi \fi   } \rmfamily}{\medskip}

Please consider the following MWE - where I try to test for string equality between an parameter, and a test string prepared by a macro:  \documentclass{article}  \def\testStr#1{IOIO#1}  \newcommand{\doTest}[1]{% \edef\tmphwp{\testStr{XX}} % \typeout{=\tmphwp=#1=} % \ifx\tmphwp#1{% \typeout{~equal}% }\else{% \typeout{!not equal}% }\fi % \typeout{ ^^J } % newline in terminal stdout }  \begin{document}  \doTest{12}  \doTest{hello}  \doTest{IOIOXX}  \end{document}   Strangely, this seems to always determine strings are unequal - even if I enter specifically the right string - terminal log (from pdflatex) reports:   =IOIOXX=12= !not equal   =IOIOXX=hello= !not equal   =IOIOXX=IOIOXX= !not equal   Hmm ... I would have expected IOIOXX = IOIOXX ?!   Can anyone explain why am I not getting the expected results - and how to get the right comparison? Does this have maybe to do anything with catcodes?  Many thanks in advance for any answers, Cheers!


How to install a Logitech G402 Hyperion Fury mouse?  I tried the official website but nothing.

Can anyone tell me how to configure all the buttons on a  under Ubuntu 12.04?  Specifically, I like to make one of them just the Ctrl key (for control clicking webpages) and another one Ctrl+W to close tabs.  I also normally make the scroll wheel page down for each click (otherwise it hurts my arms to be scrolling so much).  I make pushing the wheel to the left = pageback and pushing to the right = page forward.  I've searched for other answers to this and found something related   But when I posted a followup post to solve the issue, no one responded --perhaps I made the mistake of posting to a question that had been "solved."  I'm not sure how I'm supposed to reopen a question that is pertinent to my question but doesn't quite solve mine.


I have Calibri installed because it's the default font for M$ Office and so many of my clients send me documents using this font.  But it displays without anti-aliasing which is horrible. It's like being on a Windoze machine again :-O    It only seems to happen at small sizes; it's antialiased at larger sizes. Can I disable this?  EDIT:  My /etc/fonts/config.avail/10-antialias.conf contains  <?xml version="1.0"?> <!DOCTYPE fontconfig SYSTEM "fonts.dtd"> <fontconfig> <!--  Use the Antialiasing -->   <match target="font">     <edit name="antialias" mode="assign"><bool>true</bool></edit>   </match> </fontconfig>   And  % fc-match calibri           calibri.ttf: "Calibri" "Regular"

Microsoft TTF-fonts such as Calibri and Cambria aren't rendered correctly at certain page zoom levels:    (I installed the Microsoft fonts manually by placing them in the ~/.fonts directory and updating the font cache).  Is there any way to improve Microsoft font rendering under LibreOffice?


An AWS droplet running Ubuntu is now reporting itself as Ubuntu 16.04.5 LTS but I find no reference to this version on ubuntu.com.  The latest version is showing as 16.04.4  ( )   (note cannot establish a secure connection to releases.ubuntu.com ???)  On 2018-07-20 06:57 unattended upgrades ran and upgraded: base-files  After this upgrade this box started reporting itself as: Welcome to Ubuntu 16.04.5 LTS (GNU/Linux 4.4.0-1062-aws x86_64)  Distributor ID: Ubuntu Description:    Ubuntu 16.04.5 LTS Release:    16.04 Codename:   xenial    Prior to this update this box reported it self as Ubuntu 16.04.4 LTS  How can I verify that this update is legit?

I want to know where I can find updated information about all the stable and in-development versions of Ubuntu, where I can find this information?     This question is meant to be a canonical question. It expects to answer the following questions:         Is X version stable yet?   Is X version in beta?   Is X version still supported?   What versions are still supported?   What are the versions in Beta/Alpha?   Until where X version will be supported?   Have X version ceased support?   When will be X version released?   Where I can download any release?   When will the next LTS version of Ubuntu be released?         The list is not exhaustive.


I have a bit of an odd question regarding how primitive types work in Java. When using Objects when you assign an ObjectA to be ObjectB be like such  Rectangle ObjectB = new Rectangle(); ObjectA = ObjectB;   Any calls to ObjectA refer now to ObjectB's memory location. However when using integers or other primitive types this is not the case. For example  int x = 3; int y = x; int x = 5; return y;   y will return 3, the value of x when y was initialized.  The question I have is why does assignment for objects create references in memory, whereas primitives make a copy of the values of each other? Other than the fact that this is useful, how is this implemented in Java?  I'd appreciate anyone who can provide me a greater understanding of how assignment works between primitive types and objects.

I always thought Java uses pass-by-reference. However, I've seen a couple of blog posts (for example, ) that claim that it isn't (the blog post says that Java uses pass-by-value). I don't think I understand the distinction they're making. What is the explanation?


Should I remove them. I've got a blog with evergreen content.

In my blog I publish articles with date below under it.  My questions are:   Using dates will have positive impact or negative impact? After few years of publishing the post, since my post age is old will it remain in same position of search results or it will go down? Finally, should I use published dates or not?


The main character wakes up in a rock bed from getting revived. I think it was snowing. From this moment he meets his servant that waited for his reincarnation, the story progresses and she admits him into an academy.

The MC reincarnated himself through his own magic after his party defeated the demon king. Before he used his magic to do so, he took the daughter from the demon king and traveled with her over the world. After he used his reincarnation magic he was born in a noble family where the daughter of the demon king is now working as a maid in this family. He also has an older/younger (not sure) brother. Through his knowledge he starts his training of body, swordsmanship and magic as a baby. Years later his brother wants to play with him but he denies him every time. But one day he accepts it to play tag. His brother can't catch him. After that, he requests from the mc to teach him his magic. He denied again, but made an offer. Only when he can catch him, would he teach him his magic. I hope I'm not mixing up different mangas.


Let $A\in M_3(\mathbb R$) which is not a diagonal matrix.   Let $p$ be a polynomial  (in one variable), with real coefficients and of degree $3$ such that $p(A) = 0$.  Pick out the true statements:  (a) $p = cp_A$ where $c\in \mathbb R$ and $p_A$ is the characteristic polynomial of $A$  (b) If $p$ has a complex root (i.e. a root with non-zero imaginary part), then     $p = cp_A$, with $c$ and $p_A$ as above  (c) If $p$ has a complex root, then $A$ is diagonalizable over $\mathbb C$.  I know if (b) holds then (c) will also hold.  Is there any relation between the characteristics polynomial and any other polynomial? I know that minimal polynomial will divide any other polynomial.  But how to think about these kind or problems?

Let $A\in M_3(\Bbb R)$ which is not a diagonal matrix. Let $P$ be a polynomial (in one variable), with real coefficients and of degree 3 such that $P(A) = 0$. Pick out the true statements:  a. $P = cP_A$ where $c \in\Bbb R$ and $P_A$ is the characteristic polynomial of $A$;  b. if $P$ has a complex root (i.e. a root with non-zero imaginary part), then $P = cP_A$, with $c$ and $P_A$ as above;  c. if $P$ has a complex root, then $A$ is diagonalizable over $\Bbb C$.  I guess b and c are true although I am unable to disprove a. Because A could satisfy $(X-A)$ but this is not a polynomial. Now if $P$ has a complex root, then its conjugate too is its root as the polynomial has  real coefficients. As we all know An odd degree polynomial has always a real root, what we have is three distinct roots. Since $A$ satisfies the polynomial the only difference between the characteristic polynomial and $P$ has to be a constant.


What is the motivation for demeaning the data when doing PCA. I've been told to do it, but I've never heard a good and/or intuitive reason for it. Is this a case where doing it just makes the math easier, or is it more like: if you don't do it, you'll get the wrong answer.  This is something I've been wondering about for a while.  One other question: when you demean the data, do you also need to normalize it (i.e., divide by standard deviation)?

I keep reading about instances where we center the data (e.g., with regularization or PCA) in order to remove the intercept (as mentioned in ). I know it's simple, but I'm having a hard time intuitively understanding this. Could someone provide the intuition or a reference I can read?


So I have a script that adds 2 films together using the audio from the $1.audio file. What I would like to do is rename any file in the directory with:  *.mp4    To:  *.audio    Keeping original file name.

I'm using this command to rename files:  for fname in *; do     mv "$fname" $(echo "$fname" | sha1sum | cut -f1 -d' ') done   But it only renames in the current directory. Let's say I have many directories, and each directory contains some other directories, and last directory tree contains files. I want to rename them with random characters.  I think find . -type f should work, and have tried it, but still did not get any working command.


from  (problem 13):  "For n≤20, which groups U(n) are cyclic? Make a conjecture as to what is true in general. Can you prove your conjecture?"  where U(n) is the group of natural numbers < n and co-prime to n, under the operation of multiplication (mod n)  I find that U(n) is acyclic for n = 8,12,15,16,20, but unable to form a conjecture.

When can we say a multiplicative group of integers modulo $n$, i.e., $U_n$ is  cyclic?   $$U_n=\{a \in\mathbb  Z_n \mid \gcd(a,n)=1 \}$$  I searched the internet but did not get a clear idea.


Why isn't this code working? Could you please give me some help?   I want to read 60 lines of words from the file,like"smell,", print all the values in the order, sorts the values, and prints the values again. I use compareTo as the selection sort algorithm for the String type. However, when I run the code, it shows as follow: " Exception in thread "main" java.lang.NullPointerException at practice.selectionSort(practice.java:36) at practice.main(practice.java:10)"   So what the problems of this code are? Thank you!!  import java.util.Scanner; import java.io.*; public class practice {    public static void main (String[] args) throws IOException    {       final int DATA_NUM = 60;        String[] array = new String[DATA_NUM];       readData(array);       selectionSort(array);       printData(array);     }     public static String[] readData(String[] array) throws IOException     {       String filename = "input.txt";       Scanner file = new Scanner(new File(filename));       int count = 0;       while(file.hasNext())       {          String newLine = file.nextLine();          array[count] = newLine;          count++;       }       for(int i = 0; i < array.length; i++)       {          System.out.println(array[i]);       }       return array;    }     public static String[] selectionSort(String[] array)    {       for(int x = 1; x < array.length; x++)       {          int s = x - 1;          for(int y = x; y < array.length; y++)          {             if(array[y].compareTo(array[s]) < 0)             {                s = y;                         }          }          String minValue = array[x-1];          array[x-1] = array[s];          array[s] = minValue;       }       return array;    }    public static String[] printData(String[] array)    {       for(int i = 0; i < array.length; i++)       {          System.out.println(array[i]);       }       return array;    } }

What are Null Pointer Exceptions (java.lang.NullPointerException) and what causes them?  What methods/tools can be used to determine the cause so that you stop the exception from causing the program to terminate prematurely?


This question brought up a good point about . However, were there any rules set about the size of an object that can be summoned via that charm?  Could something on the cellular or molecular level be summoned?  From the books the smallest thing I can think of would be hair that was used to disguise Harry at the wedding; also in The Goblet of Fire, a fly was summoned as well.

We know that Accio spell (aka ) has some limits:   It can be blocked (e.g. Harry couldn't Accio the Diadem in RoR in Deathly Hallows). Many more failures are listed on Wikia.   But what are the exact full rules and limitations governing the spell in Harry Potter world?   Distance?  Line-of-sight?  Knowing exact or approximate location?  Specificity of item (e.g. "Accio Broom" seemed to work for Weasleys in OotP to bring their locked-up brooms - why not just a random broom?) Types of Accio-able stuff? Can you Accio water? Lump of earth? Gases/liquids/etc...? Can you Accio based on jQuery selector (or an SQL where clause), for lack of a better description? E.g. "Accio the book that has the word 'Flammel'"? "Accio biggest green ball from this room"? Can you Accio ALL items of a kind? (the reason I thought of this whole question was seeing "Accio all guns" comment in ). Can you Accio vague stuff? ("Accio meal"). Other rules that can be inferred.   NOTE: While Wikia article has some of the info, it is clearly very lacking in details on specific rules based on specific instances in canon. I'm looking for a fully comprehensive, organized ruleset for the charm, not merely 1-2 tidbits in Wikia article.


See the comment of @DVK on this question (in desktop view, not mobile):   How to make font size of a comment big? What's the markup?  Can all users do it? Or, only selected guys have this privilege? @DVK in question is topmost guy on SFF.SE and has Gold Badge in harry-potter tag. Has something to do with that?  Update: Here's the screenshot as some guys are unable to see it:   Web Browser is Firefox for Android. I am not using any script or mod.

An issue similar to that described in  and likely to be related.  The comments for a question may vary in size:         Chrome for Android on Nexus 7 running 4.2.2 Jelly Bean. This also occurs on Firefox for Android:


Every time I open it up it freezes. I'm going to try to re-install it. Still, anyway to fix this? Thank you for your time.  PF: Still learning how to use Ubuntu so sorry if I'm not being descriptive enough.

I already did the apt-get purge, install and update thing but it still freezes when trying to start. This is what I get trying to start in terminal:  cliff@cliff-Aspire-X1301:~$ software-center 2013-06-26 17:00:29,092 - softwarecenter.ui.gtk3.app - INFO - setting up proxy 'None' 2013-06-26 17:00:29,097 - softwarecenter.db.database - INFO - open() database: path=None use_axi=True use_agent=True 2013-06-26 17:00:29,501 - softwarecenter.backend.reviews - WARNING - Could not get usefulness from server, no username in config file 2013-06-26 17:00:29,653 - softwarecenter.ui.gtk3.app - INFO - show_available_packages: search_text is '', app is None. Killed


This is the question : Prove that the set of all the words in the English language is countble (the set's cardinality is אo) A word is defined as a finite sequence of letters in the English language.  I'm not really sure how to start this. I know that a finite union of countble sets is countble and i think this is the way to start.  Thanks in advance !

Today in Coding/Cryptography class, we were talking about basic definitions, and the professor mentioned that for a set $A=\left \{ \left. a, b, \dots, z \right \} \right.$ (the alphabet) we can define a set $A^{*}=\left \{ \left. a, ksdjf, blocks, coffee, maskdj, \dots, asdlkajsdksjfs \right \} \right.$ (words) as a set that consists of all finite sequences of the elements/letters from our $A$/alphabet. My question is, is this set $A^{*}$ countably or uncountably infinite? Does it matter how many letters there are in your alphabet? If it was, say, $A=\left \{ \left. a \right \} \right.$, then the words in $A^{*}$ would be of form $a, aa, aaa, \dots$ which, I think, would allow a bijection $\mathbb{N} \to A^{*}$ where an integer would signify the number of a's in a word. Can something analogous be done with an alphabet that consists of 26 letters (Latin alphabet), or can countability/uncountability be proved otherwise? And as mentioned before, I am wondering if the number of elements in the alphabet matters, or if all it does is change the formula for a bijection.   P.S. Now that I think of it, maybe we could biject from $\underset{n}{\underbrace{\mathbb{N}\times\mathbb{N}\times\mathbb{N}\times\dots\times\mathbb{N}}}$ to some set of words $A^{*}$ whose alphabet $A$ has $n$ elements? Thanks!


I noticed that the search engine that brings up possible duplicate questions while you're typing a question works great.  Is there a way to use the same search engine in the 'Search Q&A' search box?

I wanted to open a question titled "What's the best SQLite Cocoa library?". The suggestions told me that the question might be closed for being subjective, but also suggested some similar questions. The answer I found this way was better than the answers that I found when I searched using the search box. In fact, the question I found didn't even appear in the list from the direct search.   Is there some way to use the better search without opening a question? Is there a reason they're so different?


The exercise is taken from Rudin, principles of mathematical analysis, chapter 2 ex. 1.  Let $A$ a set and let also $B$ such that $A \cap B = \emptyset$ This implies:  $$ \emptyset = A \cap B \subseteq A, $$  For given $A$ the set $B$ can always be found, for example take $B = A^C$, the complement of $A$. Is such proof correct?

Recently I learned that for any set A, we have $\varnothing\subset A$.  I found some explanation of why it holds.     $\varnothing\subset A$ means "for every object $x$, if $x$ belongs to the empty set, then $x$ also belongs to the set A". This is a vacuous truth, because the antecedent ($x$ belongs to the empty set) could never be true, so the conclusion always holds ($x$ also belongs to the set A). So $\varnothing\subset A$ holds.   What confused me was that, the following expression was also a vacuous truth.     For every object  $x$, if $x$ belongs to the empty set, then $x$ doesn't belong to the set A.   According to the definition of the vacuous truth, the conclusion ($x$ doesn't belong to the set A) holds, so $\varnothing\not\subset A$ would be true, too.  Which one is correct? Or is it just a convention to let $\varnothing\subset A$?


Just seen someone has created this silly tag:   Should it/can it be removed?

During the re-tagging of questions, tags sometimes become orphaned from existing questions.  Are these zombie tags ever removed from the ?  What if a tag is misspelled and needs to be removed? How do we get rid of it?


What package should install for this header (err.h) is available?  I need this library (linux/err.h) to compile a proprietary driver (kernel module) in Ubuntu 14.04 Server/Desktop 64bits

Simple enough question: is there some shell command (or GUI method) I can use that, given the path to a file on my system, tells me what package put it there? Assuming the file did in fact come from a package, that is.  Bonus question: what if it's a file that isn't installed on my system? Is there, say, a website that will let me look up a file and see what packages, if any, provide it?


I'm using the method setString(String name, String val) from Query Class of Hibernate.   import org.hibernate.Query;  String q = "from Table n where n.field=:annee "; Query query= session.createQuery(q); query.setString("annee","");   I want to store an empty String and not a null, because this field can not be null in my database. But I get an error message saying that I cant insert a null value.   I don't understand what happens. Because an empty string is not  null.  It is the Query method who converts the empty chain into a null, and then Oracle gives me the error?. Or its Oracle itself who converts an empty string into a null, and then it complains?

I know that it does consider ' ' as NULL, but that doesn't do much to tell me why this is the case.  As I understand the SQL specifications, ' ' is not the same as NULL -- one is a valid datum, and the other is indicating the absence of that same information.  Feel free to speculate, but please indicate if that's the case.  If there's anyone from Oracle who can comment on it, that'd be fantastic!


I don't know much about regular expressions. I need to extract a single word enclosed by left and right parentheses in a string.   For instance, in string  (ROOT (S (NP (NNP Washington) (NNP (CNN)) (NNP Donald) (NNP Trump)) (VP (VBD was) (VP (VBN asked) (PP ( by) (NP (NP (DT a) (NN member)) (PP (IN of) (NP (DT a) (NNP Fox) (NNP News) (NN town) (NN hall) (NN audience))))) (NP-TMP (DT this) (NN week)) (SBAR (WHNP (WP what)) (S (NP (PRP he)) (VP (MD would) (VP (VB do) (S (VP (TO to) (VP (VB reduce) (NP (JJ violent) (NN crime)) (PP (IN in) (NP (DT the) (NNS country's) (JJ inner) (NN cities.)))))))))))))) (NN debate,)) (ADJP (JJ due) (S (VP (TO to) (VP (VB be) (VP (VBN broadcast) (S (NP (JJ live)) (ADJP (RBS most) (RB everywhere.))))))))))))))))   I need to get (CNN) and ( by) substrings.  EDIT      def fixeup_tree_string(T):             change_index=[]             Match = [(m.start(0), m.end(0),'Y') for m in re.finditer(r"\(\s*[\w|#|~|!|@|#|$|%|^|&|*|<|>|.|,|;|:|`|'''|_|-|+|/]+\s*\)", T)]             if len(Match)==0:             return T              if Match[0][0]!=0:             change_index.append((0,Match[0][0],'N'))             for i in range(len(Match)-1):                 change_index.append(Match[i])                 change_index.append((Match[i][1],Match[i+1][0],'N'))                 change_index.append(Match[-1])                 if Match[len(Match)-1][1]< len(T):                   change_index.append((Match[len(Match)-1][1],len(T),'N'))              new_T = []             for r in change_index:             if r[2]=='N':                 for i in range(r[0],r[1]):                     new_T.append(T[i])             else:                 str = T[r[0]:r[1]].replace(' ','')                 str = str.split(')')[0].split('(')[-1]                 str = '(NN '+str +')'                 for x in str:                     new_T.append(x)             new_T = (''.join(new_T))             return new_T

I don't really understand regular expressions.  Can you explain them to me in an easy-to-follow manner?  If there are any online tools or books, could you also link to them?


Suppose that a sequence $\{a_n\}_{n\geqslant 1}$ satisfies:      $$a_{m+n}\leqslant a_m+a_n$$      for all integers $m,n\geqslant 1$. Show that $\frac{a_n}{n}$ either converges or diverges to $-\infty$ as $n\to \infty$.   Resolution: For an arbitrarily fixed positive integer $k$ we put $n=qk+r$ with $0\leqslant r<k$. Applying the given inequality for $q$ times we get $a_n=a_{qk+r}\leqslant qa_k+a_r$; so,  $\frac{a_n}{n}\leqslant\frac{a_k}{k}+\frac{a_r}{n}$  Taking the limit as $n\to\infty$, we get   $\lim \sup_{n\to\infty}\frac{a_n}{n}\leqslant\frac{a_k}{k}$.  The sequence $\frac{a_n}{n}$ is therefore bounded above. Since $k$ is arbitrary, we conclude that:  $\lim \sup_{n\to\infty}\frac{a_n}{n}\leqslant \inf_{k\geqslant 1}\frac{a_k}{k}\leqslant\lim \inf_{k\to\infty}\frac{a_k}{k}$,  which concludes the proof.  Question:  1) First the author says that $k$ is a fixed positive integer. However in the last expression $\lim \inf_{k\to\infty}\frac{a_k}{k}$ the author makes $k$ vary. How is this supposed to prove that $\frac{a_n}{n}$ converges since the behaviour of $\lim \inf_{k\to\infty}\frac{a_k}{k}$ is not known? Why is $k$ allowed to vary?  2)On the question it is mentioned the divergence to $-\infty$. How was that point addressed in the answer or resolution?  Thanks in advance!

Let $a_1,a_2,\ldots$ be a sequence of positive real numbers. Suppose that $a_{m+n}\leq a_m+a_n$ for all $n\geq 1$. Does $\lim_{n\rightarrow\infty}\dfrac{a_n}{n}$ always exist?  From $a_{m+n}\leq a_m+a_n$ we know that $a_n\leq na_1$, so that $\dfrac{a_n}{n}\leq a_1$, which means the sequence $\dfrac{a_n}{n}$ is bounded both from above and below. But this is not enough to conclude that the limit exists.


Can't solve $\int_{0}^{+\infty}\frac{x-\sin{x}}{x^3}dx$. Try to use $\sin{x}=\frac{e^{ix}-e^{-ix}}{2i}$ and $\sin{x}=\Im{e^{ix}}$ but also can't solve this integral. Any suggestions how to solve it? Thanks in advance.  Edit:  If i use: $\sin{x}=\Im{e^{ix}}$:  $\int_{0}^{+\infty}\frac{x-\sin{x}}{x^3}dx$ = $\int_{0}^{+\infty}\frac{x-\Im{e^{ix}}}{x^3}dx$ = $\Im{\int_{0}^{+\infty}\frac{x-e^{ix}}{x^3}dx}=\Im{I}$  Then calculate $I$ using residue theorem: $I=2\pi i (res_{z=0}{f(z)})=2\pi i \frac{1}{2}=\pi i \Rightarrow$  $\Im{I}=0$ and that isn't correct answer, because correct answer is $\pi/4$.

Show that $$\int_{0}^{\infty} \frac{x - \sin(x)}{x^3} \, dx = \frac{\pi}{4}$$   My attempt is as follows: Let $$f(z) = \frac{z - i e^{iz}}{z^3}$$ and consider the contour on $[\epsilon, R]$ followed by a semicircular arc in the counter clockwise direction, then on $[-R, -\epsilon]$, then the semicircular clockwise contour avoiding the origin. We have, then, that  $$0 = \int_{\Gamma} f(z) dz = \int_{[\epsilon, R]} f(t) dt + \int_{C_R}f(Re^{it})Rie^{it}dt + \int_{[-R, -\epsilon]}f(t)dt + \int_{C_{\epsilon}}f(\epsilon e^{-it})\epsilon i e^{-it} dt$$  Then the first and third integrals ( $I_1$ and $I_3$) combine so that  $$I_1 + I_3 = 2\int_{\epsilon}^R \frac{t - \sin{t}}{t^3}\,dt$$  Further,   $$|I_{C_R}| \leq \int_0^\pi \left|\frac{Re^{it} - ie^{-R\sin{t}}e^{iRcos{t}}}{R^2 e^{2it}} \right|dt \rightarrow 0 \text{ as } R\rightarrow \infty$$  (I've omitted the details, it isn't too bad to bound)  However, I'm having trouble computing the limit  $$\lim_{\epsilon \rightarrow 0}\int_{C_{\epsilon}} f(\epsilon e^{-it})\epsilon i e^{-it} dt$$  No matter which way I look at it, it seems like this limit does not exist. Perhaps I'm seeing something wrong or have I chosen a bad $f(z)$?


How can i format an exponent with more than one digit? For example i want $10^20$ and latex gives me 10^2 and 0.

$8^(a - b)$ produces only a superscripted (; the rest of the power is not superscripted.  How can I superscript the whole (a-b) portion?


Which means, at the moment, are the safest for screening data in php to send them to the mysql database.  Thank, you )

If user input is inserted without modification into an SQL query, then the application becomes vulnerable to , like in the following example:  $unsafe_variable = $_POST['user_input'];   mysql_query("INSERT INTO `table` (`column`) VALUES ('$unsafe_variable')");   That's because the user can input something like value'); DROP TABLE table;--, and the query becomes:  INSERT INTO `table` (`column`) VALUES('value'); DROP TABLE table;--')   What can be done to prevent this from happening?


I'm testing this in IPython.  The variable t is being set from text in a dictionary and returns:   u'http://www.amazon.com/dp/B003T0G9GM/ref=wl_it_dp_v_nS_ttl/177-5611794-0982247?_encoding=UTF8&colid=SBGZJRGMR8TA&coliid=I205LCXDIRSLL3'   using this code:  r = r'amazon\.com/dp/(\w{10})'  m = re.findall(r,t)   matches correctly and m returns [u'B003T0G9GM']  Using this code,  p = re.compile(r) m = p.match(t)   m returns None  This appears correct to me after reading this documentation.   I also tested here to verify the regex before trying this in IPython   What am I missing?

What is the difference between the search() and match() functions in the ?  I've read the  (), but I never seem to remember it.  I keep having to look it up and re-learn it.  I'm hoping that someone will answer it clearly with examples so that (perhaps) it will stick in my head.  Or at least I'll have a better place to return with my question and it will take less time to re-learn it.


Quick google search for factorial of non-integers led me to . I tried that in my calculator and it worked as expected for non-integers. Perhaps implements gamma function internally.  Now, for all positive numbers:  x < y => x! < y!    But not for numbers between 0 and 1. 0! = 1!. I played around to find this:  0!      1 0.1!    0.951 0.4!    0.887 0.425!  0.886 0.45!   0.885 0.5!    0.886 0.55!   0.888 0.6!    0.893 0.9!    0.96 1!      1   What is the floor for the gamma function (or the unrestricted by integers factorial function)? The floor is around 0.45 from the table. I'm curious to know what is the floor value and the number for which gamma is minimum.  Any significance or implications of these numbers would be interesting too.

The $\Gamma (x)$ function has just one minimum for $x>0$ . This result uses some properties of the gamma function:   $\Gamma ^{\prime \prime }(x)>0$ and $\Gamma (x)>0$ for all $x>0$ $\Gamma (1)=\Gamma (2)=1$.   Observing the following graph (created in SWP) of $y=\Gamma (x)$ this minimum is near $x=3/2$, but likely $\min \Gamma (x)\neq \Gamma \left( 3/2\right) =\dfrac{1}{2}\Gamma \left( 1/2\right) =\dfrac{1}{2}\sqrt{\pi }$.     I think that it is not possible to find analytically the exact value of $x_{\min }$, even by converting to an adequate problem in the interval $]0,1]$ and using the functional equation $\Gamma (x+1)=x\Gamma (x)$ and the reflection formula  $\Gamma (p)\Gamma (p-1)=\dfrac{\pi }{\sin px}\qquad $( $0\lt p\lt 1$)    Question:   a) Which is the best way to find $\min_{[1,2]}\Gamma (x)$ and does $x_{\min }$ lay in $[1,3/2]$ or in $[3/2,2]$?  b) Is there some useful series expansion of $\Gamma (x)$?  c) Which numeric method do you suggest?    Edit:  Due to the shape of $\Gamma (x)$ I thought on the one-dimensional  method of direct search for unconstrained optimization, which approximates a function near a minimum by successive approximating quadratic polynomials.


So I have to teach partial fractions to some undergrads this week and I am looking for someone to help me understand why we solve partial fractions in cases like the following:  Suppose we have the following problem (Problem 1):  $$\int \frac{x^2-29x+5}{(x-4)^2(x^2+3)}$$  And we can decompose the integrand like the following: $$\frac{x^2-29x+5}{(x-4)^2(x^2+3)}= \frac{A}{(x-4)}+\frac{B}{(x-4)^2}+\frac{Cx+D}{(x^2+3)}$$  Contrast this with this problem (Problem 2):  $$\int \frac{3x+11}{(x-3)(x+2)}$$  We can decompose that by the following:  $$\frac{3x+11}{(x-3)(x+2)}= \frac{A}{(x-3)}+\frac{B}{(x+2)}$$  Note the second and third terms in the decomposition of Problem 1 and contrast that with both of the terms in the decomposition of Problem 2. What I do not understand is why we tack on an "x" onto our constant "C" in Problem 1. I also don't quite understand why there isn't an "x" tacked onto our constant "B" as well in Problem 1.  My question is not about how to solve either Problem 1 or Problem 2, but my question is how to explain this to undergraduates. I could go in front of my class and just explain to them the general rule to follow, but I like to provide some sort of intuition behind the rule so they aren't blindly following a step by step procedure without thinking.

I'm learning about partial fractions, and I've been told of 3 types or "forms" that they can take  (1) If the denominator of the fraction has linear factors:  $${5 \over {(x - 2)(x + 3)}} \equiv {A \over {x - 2}} + {B \over {x + 3}}$$  (2) If the denominator of the fraction has quadratic factors that don't factorise:  $${{2x + 3} \over {(x - 1)({x^2} + 4)}} \equiv {A \over {x - 1}} + {{Bx + C} \over {{x^2} + 4}}$$  (3) If the denominator has a factor that repeats:  $${{5x + 3} \over {(x - 2){{(x + 3)}^2}}} \equiv {A \over {x - 2}} + {B \over {x + 3}} + {C \over {{{(x + 3)}^2}}}$$    I'd appreciate it if someone could explain to me how these equivalence relationships are derived, essentially how do they take the forms that they do? I sort of understand the first one, but the other two I don't.  Thank you


Which is correct:   He was taken to hospital? He was taken to the hospital?

Why do British speakers omit the article in constructions like "go to hospital" or "go on holiday"? Pretty much all American speakers would rephrase those as "go to the hospital" and "go on a holiday", I think. Is there any good reason, or forgotten sense behind those words that might explain why the articles are ommitted?  Are there other common constructions other than those two that the British use that drop the article?  EDIT: I just realized per Kosmonaut's comment that Americans do much the same thing with a few nouns, so this isn't all that special.   Do grammaticists designate nouns that can have their article dropped with anything, i.e. do they have anything in common?


Why is that the all planets move in the same plane?(correct me if I'm wrong)  Why not some of them in anticlockwise direction and others in clockwise direction?

Most images you see of the solar system are 2D and all planets orbit in the same plane. In a 3D view, are really all planets orbiting in similar planes? Is there a reason for this? I'd expect that the orbits distributed all around the sun, in 3D. Has an object made by man (a probe) ever left the Solar System?


Can anyone give me an example of how to do that?

I use a basic Post to send data to a Django server.  The data consists of a base64 encoded 640*380 PNG image dynamically created by the flex component.  <mx:HTTPService id="formSend" showBusyCursor="true"      useProxy="false" url="http://127.0.0.1/form/"      method="POST" result="formSentConfirmation(event)"    fault="formSendingFailed(event)"/>    private function sendForm(url:String, message:String, meteo:Number):void {     formSend.url = url;     var params:Object = { message: message, image_data: getEncodedImage() };      snapButton.label = "sending ...";     formSend.send(params); }   On the server side i can see that the data is in the request.POST not in request.FILES. That means the image is not send as a File with multiencode HTTP.   Will i get into trouble on a real server ? since the limit is 200k for urlencoded POST var. How to make HTTPservice send the data as a file? Any other solutions?   Thanks


Consider a linear operator $T$ on finite dimensional vector space $V$. Let $\lambda$ be a root of the minimal polynomial of $T$ with multiplicity $m$. Let $V^{\lambda}=\{v\in V|Tv=\lambda v\}$. Then, is it true that the dimension of $V^{\lambda}$ is inbetween $1$ and $m$, inclusive? I think yes, andam thinking of a proof along the lines of considering the powers of $T$ and its operations on $V^{\lambda}$. Any  hints? Thanks beforehand.

The algebraic multiplicity of $\lambda_{i}$ is the degree of the root $\lambda_i$ in the polynomial $det(A-\lambda)$. The geometric multiplicity is the dimension of the eigenspace of eigenvalue $\lambda_i$.  For example: $\begin{bmatrix}1&1\\0&1\end{bmatrix}$ has root 1 with algebraic multiplicity 2, but the geometric multiplicity 1.  My question is : why geometric multiplicity is always bounded by algebraic multiplicity?  Thanks.


I discovered that inside the ~/Library/Mobile Documents folder is a trove of directories for what seems like every app that has been granted access to a user's iCloud drive. Some of these folders can be accessed via Manage Storage and selecting the associated app. However, there are folders from apps that have been uninstalled. Is there a way to remove these folders? I've tried using Terminal, but it acts like the folder doesn't exist.

There are some folders in ~/Library/Mobile Documents/ (like XXXXXX~com~companyname~appname) which seems to be left by apps I already removed from all my devices. However, if I delete those folders, they restored back almost immediately. They are not visible in Finder or in iCloud management in System Preferences. How to get rid of them?


junit 4.10 how to get the test case name printed before the test starts running..  So here I want to print "sampleTest".  How do I do it in junit 4.10 ? Thank you in advance  class1: TestSuite all = new TestSuite(); all.addTestSuite(class2); all.run(result);  class2: public class profileTest extends TestCase() {   //I want to print the test cases name before the test actually starts executing      @Test     public void sampleTest1(){         //Some code here.     }      @Test     public void sampleTest2(){     //some more code here.     } }

In JUnit 3, I could get the name of the currently running test like this:  public class MyTest extends TestCase {     public void testSomething()     {         System.out.println("Current test is " + getName());         ...     } }   which would print "Current test is testSomething".   Is there any out-of-the-box or simple way to do this in JUnit 4?  Background: Obviously, I don't want to just print the name of the test. I want to load test-specific data that is stored in a resource with the same name as the test. You know,  and all that.


This is the original question: Prove the following characterization of convergence. If $\{x_{n}\}$ is a convergent sequence, then $\forall \varepsilon >0$ there is an $N(\epsilon) \in \mathbb{N}$ so that whenever $m,n\geq N(\epsilon)$, it follows that $$|x_{m}-x_{n}|<\varepsilon.$$ I know how to show something converges by using the definition of convergence for specific equations, but I have never written a proof for a general case. Any help on how to prove this would be very helpful!

Proof that $\lim{a_n}=L$ when $n$ goes to infinity, then $\{a_n\}$ its a Cauchy Sequence  I start with this hypothesis  $\displaystyle\lim_{n \to\infty}{a_n}=L \Leftrightarrow{\forall{\epsilon}>0}$  $\exists{N}\in{\mathbb{N}}$ such that  $\forall{n}>N \left |{a_n-L}\right |< \epsilon$  The same its true fot any $m>N,\left |{a_m-L}\right |=\left |{L-a_m}\right |< \epsilon$  I will sum the inequalities but I havent any idea how do it... Help me please!!!


This is an exercise in the book by Titchmarsh, 'the theory of functions', page 242.   The answer is $\frac{1}{2}\sqrt{\pi /(1-x )} $.   How to prove it?   It is a little bit surprising to me. The function $1/\sqrt{1-x} $ has a quite different Taylor expansion around $x= 0 $.

I need some suggestions, hints for the limit when $a \to 1^{-}$ of $$\sqrt{\,1 - a\,}\,\sum_{n = 0}^{\infty}a^{n^{2}}.$$


We are having a debate at my work on if "are" or "is" is the right word to use in the above sentence (actually, a similar sentence which is work-related).  I am aware that there are other ways of rewriting this sentence which avoids this confusion, but keeping the sentence structure in-tact, what is the right word to use here? and why?     Which houses ____ this road connected to?         are   is      First time poster here. Be gentle.

Over at stats.stackexchange we are having a minor kerfuffle over whether a title is using incorrect grammar. It has been edited and re-edited several times. It would be great to get some arbitration and a clear explanation.   The original title was "What questions is your data team hoping to answer?" which was edited to "What questions are your data team hoping to answer?", then edited back. See the question .


Roughly 10 years ago, I started reading a YA novel from my school library that I believe was some kind of low fantasy/dystopian story. I remember almost nothing about it, except that the main character was a girl (possibly with a younger sibling, though I'm not sure of this).  The city she lived in was set up in such a way that everyone was divided into several different 'classes' each regulated to a certain section of the city (possibly set up in rings or wedges, poorest on the outside, richest on the inside). Each with their own colour (I think red was the poorest, or one of, and that was the colour of the main character's class).  I don't remember the plot or any particular incidents, as I don't think I got very far into the book.

I'm trying to find the name of a book series I read about 10 years ago. It might be a children/young-adult series since I was fairly young. There is also a small chance it was written by a french author, as I read it in french. The series is composed of at least three books, maybe more. Here is what I remember :   The main character is a poor girl/young woman, but there are several point of view characters At the beginning of the first book the plot is set in a city where rich people live in the city center and the further you go from the center the poorest people are. Moreover, the houses are painted according to the wealth of the owner. It was something like : the richer had red houses, the poorer blue houses, and the moderately wealthy purple (it was not those colors in particular but it was something like that) At the end of one of the book there is some kind of uprising and the people paint all the houses in multiple colorful shades (to symbolize the new found equality between the citizen) At some point the main character and other peoples of the city get captured (maybe after some kind of war the city was involved in), separated and sold to slavery One of them, an older boy, become a soldier and learn a special fighting technique that looks like dancing (and he grows to like it) Another of the captives, a young girl (the sister of the main character if I recall correctly) get marked with a fire-heated mark to show her condition of slave   That is all I remember, I have no clue about the time or geographic setting nor the story details.  I know it's not much to go by, any help would be greatly appreciated, as I would like to find these books and read them again.


Looking at the  for the 2015 dba.se election, I see the first few results look like this: 1 0 1 2 0 1 0 1 3 0 1 0 2 3 0 1 0 3 1 0 1 0 3 2 0  According to Jeff's , the first column is the weight of the vote, and the last column is an end-of-vote record marker, leaving the numbers between the first and last columns indicating which candidate was voted for. What does the 0 indicate in the column directly after the "weight" column?  Does that mean the voter did not choose a "1st choice" candidate?  They only chose a 2nd and 3rd choice?  If that is what it means, why are we allowing people to not specify their 1st choice?

In exploring the ballots available for download from Stack Exchange elections, the Code Review community came across some unexpected values in the ballot data. Background First, the specification, as far as we can tell, for the *.blt file indicates that each ballot line indicates a weight/count, and then the id's of the candidates that were part of that ballot, followed by a 0. For example, an entry: 1 7 4 9 0  would indicate 1 vote for first-choice candidate 7, then 2nd choice candidate 4, and third-choice candidate 9. The evidence for this specification comes from two places. Here, . A second reference is  I am uncertain of how official that reference is, but it agrees with Jeff. What is clear is that if a voter only chooses a subset of the available candidates, that their ballot will be 'shorter' than other ballots. For example, in Jeff's answer, there is the data: 1 1 4 2 3 0  # The first number is the ballot weight (>= 1). 1 1 2 4 3 0  # The last 0 is an end of ballot marker. 1 1 4 3 0    # Numbers in between correspond to the candidates 1 3 2 4 1 0  # on the ballot. 1 3 4 1 2 0 1 3 4 1 2 0  # Chuck, Diane, Amy, Bob 1 4 3 2 0 1 2 3 4 1 0  # last ballot  The 3rd and 7th lines indicate ballots which do not have a full complement of candidates voted for. Herein lies the problem. In the SE election data, there are 'occasional' references to candidate 0, who does not exist, and should not exist. Here are the first 10 or so "odd" ballots  ( and more than 27,000 ballots in total): 27: 1 0 7 0 0 384: 1 0 9 2 0 498: 1 0 4 7 0 508: 1 0 4 0 0 833: 1 3 0 5 0 964: 1 0 8 0 0 970: 1 1 0 9 0 1016: 1 10 0 9 0 1103: 1 5 0 6 0 1230: 1 0 5 0 0 ....  The number before the colon is the ballot line number from the above file/dataset () Questions Given the above, it is somewhat logical to assume that the odd-valued ballots are a result of voters not choosing all of the 1st, 2nd, and 3rd choice candidates. I.e. a voter who only selected a 2rd-choice candidate (candidate 5) may have a ballot like 1 0 5 0 0 While that is a logical assumption, it is also non-conformant to the specification. That vote should be registered as 1 5 0  So, is our assumption correct that the system is producing a 'bad' file for some votes as a result of not choosing all candidates?  If not, why are there 0-values in the candidate-space for ballots?  should the ballot system be audited to ensure that votes are not being 'spoiled' inadvertently (i.e. are we sure that the OpenSTV tool can handle this "bad data" appropriately)?


I'm attempting to add a Lead using the SOAP API via .NET.  I receive this error:      Unable to create/update fields: Address. Please check the security settings of this field and verify that it is read/write for your profile or permission set.   However, everywhere I can think to check shows the field is visible and editable.  Editing field-level security for Address in Lead:    Editing field visibility for Address in Lead:    Editing field-level security for the System Administrator profile, from the Profiles management tool:    What am I missing?

I'd like to create a lead via apex and set it's address. I've read that Address is a compound field and that it is totally read only unless via SOAP/REST API. Looking at the docs, I could only find getter methods - nothing to set a value.  How do I go about setting an address via apex?  Thank you!


If voltage means the pressure that makes the electrons move from the negative side to the positive one doesn't that mean that the more the voltage there is the faster the electrons move? But the electrons have the speed of light right? does that mean that it will exceed the speed of light if the voltage was big enough.

If current is the rate of flow of electrons past a point. Let's say a wire is full of electrons, and of course they pretty much are already going the speed of light, minus friction. What would increasing the voltage do?   You can't go faster than the speed of light, and you can't increase the rate of electrons because no more fit in the tube. I am just curious what this would look like. I feel like I am missing a key concept.


I have a stored procedure that I need to pass a comma-delimited variable to.  For example, if a certain condition exists, I would pass a list of country codes like this:  AU,RA,PK   The number of items can vary.  In the stored procedure, I need to use those items in an IN clause such as follows:  WHERE CountryCode IN (@ExcludeCountries)   Is there any way to do this?  I can massage the country codes going in to something like N'AU', N'RA', N'PK' if need be.  Thanks.

Is there a graceful way to handle passing a list of ids as a parameter to a stored procedure?   For instance, I want departments 1, 2, 5, 7, 20 returned by my stored procedure. In the past, I have passed in a comma delimited list of ids, like the below code, but feel really dirty doing it.   SQL Server 2005 is my only applicable limitation I think.  create procedure getDepartments   @DepartmentIds varchar(max) as   declare @Sql varchar(max)        select @Sql = 'select [Name] from Department where DepartmentId in (' + @DepartmentIds + ')'   exec(@Sql)


Let $X_1\sim N(0,\sigma_1^2), X_2\sim N(0,\sigma_2^2),\dots,X_n\sim N(0,\sigma_n^2)$ where generally $\sigma_1\neq\sigma_2\neq\sigma_3\dots\neq\sigma_n$. What is the distribution of the statistic $$Y = \sqrt{\sum_{k=1}^n X_k^2}?$$  The distribution for $Y^2$ is obtained by a combination of  and , but I don't know enough about characteristic functions to see if there's any easy way of incorporating the square root.

Let $\mathbf{X}\sim \mathcal{N}(0,I)$ be an $n-$dimensional standard Gaussian vector. We know that  $$\begin{align} ||\mathbf{X}||^2&=\sum_{i=1}^nX_i^2\sim\chi^2_n\\ ||\mathbf{X}||&=\sqrt{\sum_{i=1}^nX_i^2}\sim\chi_n\\ \end{align}$$  Suppose the components are correlated, i.e., we consider $\mathbf{Y}\sim \mathcal{N}(0,\Sigma)$ where $\Sigma$ is positive definite. We know that $||\mathbf{Y}||^2$ has the . Is there also a corresponding generalized chi distribution for $||\mathbf{Y}||$? If so, is there some asymptotic result on the mean of such a distribution for $n\to\infty$? This is related to       But here the components of the random vector are neither independent or identically distributed.


This might be one of those "it already exists" feature requests / support questions.   But is there a way to see the history of questions you've visited in Stack Overflow, maybe even like the last 100 or something similar to the unix history command?   There has been times when I've stumbled across something and need to go back to it and it is not findable via Google (and I didn't favorite) nor back button. Ideally a history by tag would be really cool.   So, I use SO on laptop / Chrome and iPad / Safari. Browser history is not sufficient.

I always search in my history browser to find the last questions that I have visited recently, so I spend a lot of time trying to search in my history browser which contains a lot of links. Some times I can't find the link if I cleared the history cache or if I'm connected from an other PC.  It's really easy to realize this feature, this will be done, just by storing the ID of the current subject, and list all those links on a page on the activity tab, or just a client side solution that list all the recent visited subjects on the current session.


$f(x)=\log{\frac{x}{1+\sqrt{5-x^2}}}$  I have to find the derivative of $f(x)$. Please tell me if my steps are correct.  $\frac{1+\sqrt{5-x^2}}{x}×\frac{1}{\ln 10}×\frac{1+\sqrt{5-x^2}-x×\frac{1}{2\sqrt{5-x^2}}}{(1+\sqrt{5-x^2})^2}×\frac{1}{2\sqrt{5-x^2}}×(-2x)$

I have to calculate the derivative of this:  $$f(x)=\log_{10}{\frac{x}{1+\sqrt{5-x^2}}}$$  But I'm stuck. This is the point where I have arrived:  $$f'(x) = \frac{(1+\sqrt{5-x^2})(\sqrt{5-x^2})+x^2}{x(\ln 10)(1+\sqrt{5-x^2})(\sqrt{5-x^2})}$$  How can I simplify? I didn't include all the passages.


Does anyone have or can derive any LaTeX code of the form of this tricky table? Thank you    \documentclass{article}  \usepackage{multirow}  \begin{document}  \begin{tabular}{|cc||c|c|c|} \hline \multicolumn{2}{|c||}{\multirow{2}{*}{Word}} & \multicolumn{3}{c|}{Word}\\ \cline{3-5} & & 1 & 2 & 3\\ \hline \multirow{5}{*}{Word} & \multicolumn{1}{|c||}{1} & & &\\ \cline{2-5} & \multicolumn{1}{|c||}{2} & & &\\ \cline{2-5} & \multicolumn{1}{|c||}{3} & & &\\ \cline{2-5} & \multicolumn{1}{|c||}{4} & & &\\ \cline{2-5} & \multicolumn{1}{|c||}{5} & & &\\ \hline \end{tabular} \end{document}

I really tried hard to do this on my own, but I keep failing ... Using multi-column and multi-row commands confused me. I know some of you might frown upon such a request but I really need help getting this table implemented .. So I'm sorry if I upset anyone.  My preamble has :   \documentclass[12pt,a4paper]{report} \usepackage[lmargin=3.81cm,tmargin=2.54cm,rmargin=2.54cm,bmargin=2.52cm]{geometry} \linespread{1.5}     Is there a way I can convert this from excel to LaTeX form ? I tried an add-in before but it didn't work for me. Also online generators cannot combine cells the way I want them (unless I didn't find a better table generator ? )


Should be prefer reinterpret_cast over C style casting. Please explain.  Which one should be preferred if one has to choose between reinterpret_cast and c style casting

What are the proper uses of:   static_cast dynamic_cast const_cast reinterpret_cast C-style cast (type)value Function-style cast type(value)   How does one decide which to use in which specific cases?


How do you impress the interviewer, when he asks you to compute $\sqrt{2+\sqrt{2+\sqrt{2+...}}}$?

(Fitzpatrick Advanced Calculus 2e, Sec. 2.4 #12)  For $c \gt 0$, consider the quadratic equation $x^2 - x - c = 0, x > 0$.  Define the sequence $\{x_n\}$ recursively by fixing $|x_1| \lt c$ and then, if $n$ is an index for which $x_n$ has been defined, defining  $$x_{n+1} = \sqrt{c+x_n}$$  Prove that the sequence $\{x_n\}$ converges monotonically to the solution of the above equation.  Note: The answers below might assume $x_1 \gt 0$, but they still work, as we have $x_3 \gt 0$.    This is being repurposed in an effort to cut down on duplicates, see here: .  and here: .


I have 100 cards labelled from 1 to 100. I place this in a row with all the cards face down. On the first turn I flip the first card. Now this card has a number $n$ on it. I then put this card face-up in the $n$-th position, and flip the original $n$-th card. I then continue this process until I eventually get back the card labelled 1. I will call this a cycle. Now I repeat this process by flipping the next card (from the start) that is not yet face up and continue this process until all 100 cards are face up.   After this process is completed, what is the average number of cycles that I obtain? (An example of some cycles could include $1\rightarrow41\rightarrow57\rightarrow79\rightarrow1$, $2\rightarrow65\rightarrow35\rightarrow71\rightarrow2$, $3\rightarrow3$, etc.

There is a party with 20 people, and everyone writes their name down   on a piece of paper and puts it into a bag. The bag is mixed up, and   each person draws one piece of paper. If you draw the name of someone   else, you are considered to be in his "group". What is the expected   number of groups after everyone draws?   So basically if we have a loop where each person draws someone else's name, and the last person draws the first person in that list's name, we have a group. Not quite sure how to approach this problem.  Thanks for any help.