Why i am getting this exception?  I am new to java and stackoverflow  ArrayList<A> a = new ArrayList<A>(); ArrayList<B> b = new ArrayList<B>();  a.add(new A("A")); a.add(new A("B")); a.add(new A("C"));  b.add(new B(new A("A"), "a")); b.add(new B(new A("B"), "b")); b.add(new B(new A("C"), "c"));  System.out.println(a); System.out.println(b);  bIterator = b.iterator(); while(bIterator.hasNext()) {     b.add(new B(bIterator.next(), "a")); }   error  Exception in thread "main" java.util.ConcurrentModificationException

We all know you can't do the following because of ConcurrentModificationException:  for (Object i : l) {     if (condition(i)) {         l.remove(i);     } }   But this apparently works sometimes, but not always. Here's some specific code:  public static void main(String[] args) {     Collection<Integer> l = new ArrayList<>();      for (int i = 0; i < 10; ++i) {         l.add(4);         l.add(5);         l.add(6);     }      for (int i : l) {         if (i == 5) {             l.remove(i);         }     }      System.out.println(l); }   This, of course, results in:  Exception in thread "main" java.util.ConcurrentModificationException   Even though multiple threads aren't doing it. Anyway.  What's the best solution to this problem? How can I remove an item from the collection in a loop without throwing this exception?  I'm also using an arbitrary Collection here, not necessarily an ArrayList, so you can't rely on get.


I have two minipages (actually one of them is varwidth) standing one above the other. How can I keep same baseline skip in them?  I have somewhat strange layout, so I can't set [t] option for lower minipage/varwidth.  \documentclass{article}  \usepackage[paperwidth=10cm,paperheight=5cm,showframe]{geometry}  \usepackage{varwidth}  \begin{document}  \noindent LOREM IPSUM  \vfill  \noindent\begin{minipage}[b]{\textwidth} \raggedleft  LOREM IPSUM  LOREM IPSUM \end{minipage}  \noindent\begin{minipage}[b]{.5\textwidth} LOREM IPSUM \end{minipage}% \noindent\hfill\begin{varwidth}[b]{.5\textwidth} LOREM IPSUM  LOREM IPSUM  \end{varwidth}  \end{document}

When a minipage is used to box a text paragraph, the first line of the minipaged text and the last line of the previous text paragraph are closer than two consecutive lines in a standard text paragraph; analogously, the last line of text inside the minipage and the first line of text after the minipage are also closer.  The following MWE illustrates this:  \documentclass{article} \usepackage{lipsum}  \newcommand\Text{Lorem ipsum dolor sit amet, consectetuer adipiscing elit. Ut purus elit, vestibulum ut, placerat ac, adipiscing vitae, felis. Curabitur dictum gravida mauris. Nam arcu libero, nonummy eget, consectetuer id, vulputate a, magna.\textbullet}  \begin{document}  \Text  \noindent\begin{minipage}{\linewidth} \Text \end{minipage}  \Text  \end{document}   How can I guarantee a constant baseline-skip even if minipages (or \parboxes) are used?


I have accidentally truncate mysql table table1. The truncated data are very very important. I used wampserver latest version. Unfortunately I do not have binary logs. I have wamp folder under drive C in Windows 10. Now I am trying to restore the database folder using Windows data recovery tool. Is there any other possibilities to restore my truncated table?

I am getting the "wrong input table name" when use TRUNCATE as following:  TRUNCATE `stats`   The table should bans.  How to recover stats table?  I am using CentOS 6, and MySQL-Server.


I want to validate the phone number Like 1-12 -123 using regex and I have tried like  /^[0-9 -]+$/   and  /^[0-9,\- ]+$/   Iam using it like  /^[0-9 -]+$/.test(value)   And it is accepting 0-9 numbers and - also but not accepting the spaces.I have tried in many ways but did'nt got any solution.Can anyone suggest me.Thanks in Advance

I'm trying to put together a comprehensive regex to validate phone numbers. Ideally it would handle international formats, but it must handle US formats, including the following:   1-234-567-8901 1-234-567-8901 x1234 1-234-567-8901 ext1234 1 (234) 567-8901 1.234.567.8901 1/234/567/8901 12345678901   I'll answer with my current attempt, but I'm hoping somebody has something better and/or more elegant.


I have multiple email accounts and the messages are either forwarded to one Gmail account or I get them via POP/IMAP. Now I want to simplify all that and use only one account and get rid of all others. I need to list all senders who wrote to each of my email addresses, so I can notify them about my new account or in case of websites, change my email address there.  I could search the emails like this:       "to:myOldAddress@gmail.com"   and go through all emails. But unfortunately I have too many emails.  For the people out here who understand SQL, the query would be something like this:    select FromAddress from emailsTable where ToAddress = "myOldAddress@gmail.com" group by FromAddress    Another idea is to download all emails (Google allows you that) and scan them somehow. But I'm not sure though whether I can put it in an Excel or something.  Any ideas?

How can I export a list containing e-mail addresses for everyone that has sent me an e-mail?  I have all of the messages archived.


I sent a tweet to someone. It wasn't part of an ongoing conversation. It was just something I sent to them. I asked someone in a forum I was in if they could read the tweet I had sent. This person wasn't the recipient, yet they were able to read my tweet to the other person.   I've NEVER been able to read the tweets sent to someone. If I go into someone's timeline, the only thing I see are tweets that they've sent, as well as replies, etc. But I'm not able to see tweets sent to them. Is there some setting that I"m missing? This is very frustrating.

I have tried tweeting someone I follow couple of times.  My tweets appear on my profile but when I look at the other person's timeline, my tweet is not there. I am following him but he is not following me.


I picked up an extension cord today, and I noticed that it had a different value for its wattage and its ampage, based on whether the cord is wound around its base or not.     (I apologize that the picture is blurry. In the left box it says, ”Max current wound - 4 Amps (960 Watts),” and in the right box it says, “WARNING - Max current unwound - 13 Amps (3120 Watts).”)   Why does this make a difference? Assuming that the wire is properly insulated, shouldn’t it transfer the electricity just as efficiently wound as unwound? Is there a formula that I can use to calculate a cord’s wattage/amperage when only part of it is wound, or when all of it is wound, given its wattage/amperage when straight, how much of it is wound, and how tightly it’s wound, and maybe some other variable I can’t think of?   Obviously my question assumes that it has nothing to do with a liability concern or the like.

(Disclaimer: I've read the  and I do understand that this is bordering on off-topic since it's about consumer devices. However I hope that I've managed to make enough on-topic by asking about why it is the way it is, and what is the explanation from an electromagnetic point of view - in other words, what laws of electricity and what practical considerations have gone into these decisions).  I recently bought a power tool and in its manual I found a few peculiar safety rules. I cannot see why they would be there, although reading up more it seems that they are commonplace. My understanding of electricity is limited (just about enough to be dangerous), so I'm hoping to expand it. :)  The rules are:   Don't use an extension cord longer than 25m. Considering this is an outdoors tool, this limitation is severely restrictive. The best explanation I've seen is that longer cables would simply have too high of a resistance and the tool wouldn't be able to operate at full power. But this argument doesn't convince me. The tool is rated at 2.4kW, and it's meant to be used with 220V AC power source, which means it uses about 11 amps of current. All the extension cords I've ever come across have at least 16A limitation, so there is quite a reserve still. In addition, the power has to travel much, much further to get to my house, and even after the meter it still takes probably close to those same 25m to get to the power outlet. Why only 25m after the outlet? The resistance of the cables isn't that big, is it? Don't daisy-chain extension cords. I suspect this is a variation of the above - don't exceed 25m; every connection adds additional contact resistance; water in the outdoors connections can be a problem - in general, it just adds risk. However, apart from the water in the contacts, the rest seems to me to be practically negligible. Is there really a significant contact resistance? Assuming that the extension cords are in a good shape. Make sure that the power cord is entirely unrolled. This is another odd one. My suspicion is that it has to do with inductive resistance. But is it really that strong? Wherever I've seen people actually wanting to create an electromagnet, it's pretty much hard work. You need a lot of neat, tightly-wound loops of wire. An extension cord has a lot of insulator around it, spacing the wires pretty far apart, and the loops are very chaotic. In addition, if that was a problem, why do  exist? They're used especially when you need a very long extension cord, and you don't need to unroll them completely every time you want to use them. Solved: OK, I was off the mark. The correct answer (also a ) has to do with the wire heating up from being used close to its limits. When coiled together, the temperature can go pretty high and melt the cables. Not fun.


When you different models that are trying to establish the relationship between the same variables -- but these models have different structural forms, when can you compare the $R^2 $ of these models?  For example, of the three models here:   Regressing $ Y $ on $ X $ Regressing $ Y $ on $ \ln(x) $ Regressing $ \ln Y $ on $ \ln(x) $ Regressing  $ \ln(Y) $ on $ X $   which models would be comparable?   Should I write out: $$ R^2 = \frac { \Sigma \hat{y_i}^2 }{\Sigma y_i^2} $$ and then see if the numerator and denominator have the same general structure? (For example, if the denominator of one model is in logs and the other in raw form, then the model with the raw form variables will have a higher "Total Sum of Squares", and thus lesser $ R^2 $  (I do not necessarily need direct answers on these; but a general direction will greatly help).

I'm trying to identify the best model to predict the prices of automobiles, using the prices and features available on automobile classified advertisement sites.  For this I used a couple of models from the scikit-learn library and neural network models from pybrain and neurolab. The approach I used so far is to run a fixed amount of data through some models(machine learning algorithms) and compare there $R^2$ values which was calculated with the scikit-learn metrics module.   Is $R^2$ a good method to compare the performance of different models? Although I got quite acceptable results for models such as Elastic net and Random forests I got very poor $R^2$ values for Neural network models,so is $R^2$ an appropriate method for evaluating neural networks (or non-linear methods)?


I have an app uploaded on PlayStore and getting crash on it java.lang.NullPointerException from android.app.ActivityThread.updateLocaleListFromAppContext  I have tried searching a lot online to check where this error could be coming from. I'm not natively using this method call specifically for anything in the code.  java.lang.NullPointerException:    at android.app.ActivityThread.updateLocaleListFromAppContext (ActivityThread.java:5892)   at android.app.ActivityThread.handleBindApplication (ActivityThread.java:6127)   at android.app.ActivityThread.access$1200 (ActivityThread.java:240)   at android.app.ActivityThread$H.handleMessage (ActivityThread.java:1797)   at android.os.Handler.dispatchMessage (Handler.java:106)   at android.os.Looper.loop (Looper.java:214)   at android.app.ActivityThread.main (ActivityThread.java:7076)   at java.lang.reflect.Method.invoke (Method.java)   at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run (RuntimeInit.java:494)   at com.android.internal.os.ZygoteInit.main (ZygoteInit.java:965)   Please help if anyone knows the solution or where I can start looking to resolve this.

I use object != null a lot to avoid . What is an alternative to: if (someobject != null) {     someobject.doCalc(); }


I have a small issue with my Ubuntu (I think After an upgarde). When I try to login (Login Screen), I get disconnected and get back to the screen (again & again).  I tried:   Trying to login with others Desktop environements. Booting from old kernel. log in via command line [apt-get update && apt-get upgrade]. removing ~/.gconf directory. sudo apt-get install --reinstall ubuntu-desktop and sudo apt-get install unity   None of these solutions worked.

My Ubuntu is stuck in a login loop when trying to enter my desktop. When I login, the screen gets black and soon after that the login screen comes back.   I've read that the problem might be caused by an error depending on the graphics, here's my graphics card: ATI Radeon 7670M


I don't understand how to make my usb bootable for installing windows 8.1 pro again as whenever I am trying to make my usb bootable and try to boot from it, the computer  says "no system disk or disk error please replace and strike any key".  I have a hp notebook compaq nc4400.

I'd like to create a Windows bootable USB stick, but I don't have a Windows machine with me at the moment to do so. How could I achieve the same using Ubuntu?


Let $A$ a finite $k$-algebra (with $k$ a field) and $B$ a subalgebra of $A$. Prove that if $\mathfrak{m}$ is a maximal ideal of $A$ then $\mathfrak{m}\cap B$ is a maximal ideal of $B$.   It is easy to see that $\mathfrak{m}\cap B$ is an ideal of $B$. We have to prove that $$B' = ~^{B}\big / _{\mathfrak{m}\cap B}$$ is a field. To do so, I've tried to use the following lemma :  Lemma : If $A'$ is a field and $B'$ is a subring of $A'$ such that $A'$ is a finitely generated $B'$-module then $B'$ is a field.  Let $A'=~^{A}\big / _{\mathfrak{m}}$.   $\mathfrak{m}$ is maximal, so $A'$ is a field. $B$ is a subring of $A$, so $B'$ is a subring of $A'$. $B$ is a finite subalgebra of $A$, so $A'$ is a finite $B'$-subalgebra. How do I prove that for all $x\in A'$, $x$ is an algebraic integer over $B'$? I've tried to start noticing that $A$ is a finite $k$-algebra so is $A'$ and $A'$ is a field, hence $k\subset A'$ is a finite algebraic extension but I don't see how to continue. Do we have to use Noether's Normalization lemma?   Any help will be greatly appreciate.

Let $k$ be a field and let $A \subset B$ be two finitely generated $k$-algebras. Prove that the contraction of any maximal ideal of $B$ is a maximal ideal of $A$.   thank you very much again!


Someone asked me  What if someone hides their instagram stories from you?  I replied I'd hide them from my life  Is my sentence right  Does hide mean to make disappear?  If not What else could I have used here?  Object of preposition from can not be a place like the magician hid(made her disappear) from the stage?

Someone asked me     What if someone hides their instagram stories from you?   I replied      I'd hide them from my life.   Is my sentence right  Does hide mean to make disappear?  If not What else could I have used here?  Someone told me the object of preposition "from" is a person who is not supposed to see or find that which is hidden  So what about this sentence?      the magician hid(made her disappear) from the stage?   Is it wrong?


The numbers $1,\frac{1}{2},\frac{1}{3},\dots,\frac{1}{n}$ are written on a white board. In every step we pick two numbers $a$ and $b$ and put $a+b+ab$ besides. Prove that the last number that remains is $n$.   By induction it is easy to prove:  It is true for $1$.  Think it is true for $n$  Prove it is true for $n+1$  $n+\frac{1}{n+1}+\frac{n}{n+1}=n+1$  But I want a non-induction prove.Thanks.

You're given a sequence of number: $1,\frac{1}{2},\frac{1}{3},\dots,\frac{1}{64}$.  A function takes two numbers in the sequence, say $a,b$ and replaces them both with $a+b+ab$. For example, we could take the initial sequence and apply the operation to the numbers $1$ and $1/64$ to obtain the new list $$\frac{1}{2}, \frac{1}{3},\cdots, \frac{1}{63}, \frac{33}{32}, \frac{33}{32}$$     Is there a solution so that after some number of steps, all terms in the sequence are equal? How many unique solutions are there?     Note that this question is different from the question asked , because the number of terms in that question changes, while in this question, the number of terms remains constant ($64$).  By the reasoning in the linked question, we can observe that the operation $a*b = a + b + ab = (a+1)(b+1)-1$ on $\mathbb{Q}$ is identical to the usual multiplication, under the isomorphism $(\mathbb{Q}, *) \to (\mathbb{Q}, \times)$ given by $x \mapsto x+1$.


According to :  You can use either one of the supported prettify language codes, like lang-cpp or lang-sql, or you can specify a tag, and the syntax highlighting language associated with this tag will be used: <!-- language: c# -->      public static bool IsAwesome { get { return true; } }   However, in , <!-- language: python --> fails, yet <!-- language: lang-py --> works.  is clearly a valid tag, so I'd expect both to work This also would explain why questions tagged  do not automatically use python syntax highlighting

Based on  I shouldn't need to give the lang- prefix when specifying a language for a tag, however this doesn't appear to be the case for CSS.  This is the result of specifying just <!-- language: css --> on a block of code:    Notice how the IDs (#) are being treated as comments rather than style declarations, and there is no nice formatting on the property names.  This is the result of specifying <!-- language: lang-css --> on the same block of code:    I'm not 100% sure if this is a problem, but if it is: can this be fixed?


This appears to be an easy concept, but I'm having difficulty finding out what is going on via Google:  I have a binary file generated by a C program, example_binary.   After using cat example_binary, the output looks like a typical output after running cat on a compressed file.   However, after cat has finished, letters and numbers remain on the command line. In this case, I see 1;2c.   $ cat example_binary ... $ 1;2c   Why would there be leftover numbers and letters remaining on the command line? What does 1;2c mean?

If I understand the cat manual correctly:       concatenate files and print on the standard output   cat will take files as argument and print them on standard output. What I don't get is if I use the command:    cat img.png > copy.png   I will obtain 2 png files identical while if I just    cat img.png     I have all chance that my terminal get messed up and misinterpret what I type.     How's that possible?   Binary values are still binary data. Why it does not simply shows a series of 0 and 1 or the interpretation of those binary data in ASCII or whatever the encoding in terminal is?   Is this behavior also possible by cating a text file containing strange characters?   Should a mechanism to prevent this behavior  like try{}catch{} statement should be implemented?


I am Using IMAP in order to check some emails( sometimes in Japanese, sometimes in English), and some of them I get the results encrypted in ISO-2022-JP. I was trying using $msg='=1B$B#77n=1B(B      =1B$B2V2&=1B(B          =1B$B%K%e!<%9$N$_=1B(B';  $utf8Msg = mb_convert_encoding($msg,'UTF-8','ISO-2022-JP-MS');  to decode the message, but it is not working. Do you guys have any suggestion on how I should proceed to decode any message(Japanese, English and so on) using IMAP? or is there a better way to read email in php? Like some method that already shows the decoded message?

I have the string which that encoded in .  How do I decode this in php?  Lorem ipsum dolor sit amet, consectetuer adipiscing elit. Vestibulum felis = pede, vestibulum et, ullamcorper in, ultrices eget, metus. Suspendisse in n= ulla. Sed justo. Donec dapibus auctor neque. Pellentesque faucibus ante nec=  metus. Vivamus feugiat, velit rhoncus semper suscipit, libero augue venena= tis leo, nec ornare nulla elit eget diam. Nullam sollicitudin.


I have two sharepoint farms; Live & Test. both have the following software specification.   sharepoint enterprise server 2013, with SP1. installed inside windows server 2008 R2.   now when i build our Live & Test servers , i have install sharepoint designer 2013.but lately i have read many articles which mentioned that it is recommended not to install any office or other application other than sharepoint inside sharepoint servers. so now i am planning to un-install sharepoint designer .. now on our Test server, i followed these steps:-   Control Panel. Uninstall a program. select sharepoint designer 2013. click on remove.   and the SP designer got uninstalled correctly.but before doing the same steps on on live server can any one advice on this point, if un-installing SPD can cause any harm to sharepoint serivces:-  Since both SharePoint service 2013 & SharePoint Designer 2013 are within the office suite,, so they might share some patches , updates and .dll files.. so my concern if i un-install sharepoint designer inside the sharepoint server could this remove .dll or patches which is related to sharepoint ? or un-installing sharepoint designer will not affect sharepoint and will not conflict with the .dlls , patches related to sharepoint??

I have two SharePoint farms; Live & Test. both have the following software specification.   SharePoint enterprise server 2013, with SP1. installed inside windows server 2008 R2.   Now when I built our Live & Test servers, I had installed SharePoint Designer 2013, but lately I have read many articles which mentioned that it is recommended not not install any office or other application other than SharePoint inside SharePoint servers. So now I am planning to uninstall SharePoint Designer. Now on our Test server, I followed these steps:   Control Panel. Uninstall a program. select SharePoint Designer 2013. click on remove.   SP Designer got uninstalled correctly but not sure if this is the recommended way to uninstall SP designer. Now I am planning to uninstall SP designer on live server and could uninstalling SP designer cause any problem to SharePoint ?  Since both SharePoint service 2013 & SharePoint Designer 2013 are within the office suite, they might share some patches, updates and .dll files. So my concern if I uninstall SharePoint Designer inside the SharePoint server could this remove .dll or patches which is related to SharePoint or will uninstalling SharePoint Designer not affect SharePoint and will not conflict with the .dlls, patches related to SharePoint??


What is the result of:  summation from one, two, four, eight until $n$ power of two?  Thank you!

Why does the following hold:  \begin{equation*} \displaystyle \sum\limits_{n=0}^{\infty} 0.7^n=\frac{1}{1-0.7} = 10/3\quad ? \end{equation*}  Can we generalize the above to      $\displaystyle \sum_{n=0}^{\infty} x^n = \frac{1}{1-x}$ ?   Are there some values of $x$ for which the above formula is invalid?  What about if we take only a finite number of terms? Is there a simpler formula?     $\displaystyle \sum_{n=0}^{N} x^n$   Is there a name for such a sequence?    This is being repurposed in an effort to cut down on duplicates, see here: Coping with  duplicate questions.  and here: .


I don't remember too much about this series, but here is what I do remember.    Young man somehow comes across a green demon who becomes his friend and maybe teaches him magic?  He shows him these "streams" or "veins" of magic that can be stronger or weaker depending on the place. There are all kinds of different worlds that they can jump to or travel to? they start some kind of business and set up their office in some kind of market on one of the worlds in a tent that is a lot bigger inside then out. The demons name is Azod or Azoth or something like that.    I think there were 7 or 8 books in the series. Any help would be great!

Can you help me identify a book I read?  It was intended for teenagers.  I believe I read it in the late 1980s or early 1990s.  The main character is a teenage human boy from earth, who is learning to use magic with the help of a humanoid lizard companion, who knows all about magic, but can't use magic himself.  They travel to numerous worlds.  I remember one of the lessons was to draw in magic from the ground with every step he takes.  And there are different lines or streams of magic flowing through the world.  Different areas have different concentrations of magic to draw from.  At one point they travel to another world where there is a bazaar or marketplace selling lots of different things.  I believe at one point they travel to yet another world where they are hanged.  The main character survives by lifting himself up by using magic, and the lizard companion uses his strong neck muscles to avoid being killed.  I believe there's also a house where the front door is in one world, but the rest of the house is in a different world.


My code is like  var persons = []; function Person(id, name) {     this.id         = id;     this.name       = name; }   When I am trying to loop throught all persons, I'm getting an uncaught TypeError: Cannot read property "name" of undefined.  for (var person in persons) {    console.log(persons[person]); }   I noticed that my console is logging all persons and adding an property values after them  [Person, $family: function, $constructor: function, each: function, clone: function, clean: function…]   I'm pretty sure that that the code is breaking after looping the first person.  I'm using jquery-1.11.1.js  Any ideas how to get rid of this error? Thank you in advance.

I've been told not to use for...in with arrays in JavaScript. Why not?


When: I recall seeing this when I was young so could have been early to mid 1990s. Setting: It is either based primarily in an aeroplane around the passengers and may also involve the airport but those details are a bit hazy. From what I can remember it wasn't futuristic but set at the current time. Details: the only real clear details I can recall are at the end the passengers need to go to sleep in their original positions on the plane to get out of their predicament (time loop?), however one passenger needs to stay awake in the cockpit and ends up disappearing once all the others wake up. I believe the problem facing the characters was either time travel or time loop related.

Looking for a TV episode where tiny men go around recreating the world in between seconds, behind the main characters backs/just out of sight. I think it was older. My memories say it was in Black and White. Similar concept to Twilight Zone's "Matter of Minutes," different execution.


I know that this question has been asked here before but I want to use a different approach. Here is the question.  A function $f:\Bbb{R}\to\Bbb{R}$ is such that  \begin{align} f(x+y)=f(x)+f(y) ,\;\;\forall\;x,y\in\Bbb{R}\qquad\qquad\qquad(1)\end{align} I want to show that if $f$ is continuous at $0$, it is continuous on $\Bbb{R}.$  MY WORK  Since $(1)$ holds for all $x\in \Bbb{R},$ we let \begin{align} x=x-y+y\end{align} Then,  \begin{align} f(x-y+y)=f(x-y)+f(y)\end{align} \begin{align} f(x-y)=f(x)-f(y)\end{align} Let $x_0\in \Bbb{R}, \;\epsilon>$ and $y=x-x_0,\;\;\forall\,x\in\Bbb{R}.$ Then,  \begin{align} f(x-(x-x_0))=f(x)-f(x-x_0)\end{align}  \begin{align} f(x_0)=f(x)-f(x-x_0)\end{align}  \begin{align} f(y)=f(x_0)-f(x)\end{align}  HINTS BY MY PDF:  Let $x_0\in \Bbb{R}, \;\epsilon>$ and $y=x-x_0,\;\;\forall\,x\in\Bbb{R}.$ Then, show that  \begin{align} \left|f(x_0)-f(x)\right|=\left|f(y)-f(0)\right|\end{align} Using this equation and the continuity of $f$ at $0$, establish properly that  \begin{align}\left|f(y)-f(0)\right|<\epsilon,\end{align} in some neighbourhood of $0$.  My problem is how to put this hint together to complete the proof. Please, I need assistance, thanks!

The  asks about functions $f \colon \mathbb R \to \mathbb R$ such that $$f(x+y)=f(x)+f(y).$$ It is a very well-known functional equation, which appears in various areas of mathematics ranging from exercises in freshman classes to constructing useful counterexamples for some advanced questions. Solutions of this equation are often called . Also a few other equations related to this equation are often studied. (Equations which can be easily transformed to Cauchy functional equation or can be solved by using similar methods.) Is there some overview of basic facts about Cauchy equation and related functional equations - preferably available online?


My cPanel site was hacked. The attacker has changed my cPanel password. How could he do that and how can I gain access to my site back?  Thanks.

This is a  about Server Security - Responding to Breach Events (Hacking)   See Also:                  Canonical Version I suspect that one or more of my servers is compromised by a hacker, virus, or other mechanism:   What are my first steps? When I arrive on site should I disconnect the server, preserve "evidence", are there other initial considerations? How do I go about getting services back online? How do I prevent the same thing from happening immediately again? Are there best practices or methodologies for learning from this incident? If I wanted to put a Incident Response Plan together, where would I start? Should this be part of my Disaster Recovery or Business Continuity Planning?   Original Version       2011.01.02 - I'm on my way into work at 9.30 p.m. on a Sunday because our server has been compromised somehow and was resulting in a    attack on our provider. The servers access to the Internet   has been shut down which means over 5-600 of our clients sites are now   down. Now this could be an FTP hack, or some weakness in code   somewhere. I'm not sure till I get there.      How can I track this down quickly? We're in for a whole lot of   litigation if I don't get the server back up ASAP. Any help is   appreciated. We are running Open SUSE 11.0.            2011.01.03 - Thanks to everyone for your help. Luckily I WASN'T the only person responsible for this server, just the nearest. We managed   to resolve this problem, although it may not apply to many others in a   different situation. I'll detail what we did.      We unplugged the server from the net. It was performing (attempting to   perform) a Denial Of Service attack on another server in Indonesia,   and the guilty party was also based there.      We firstly tried to identify where on the server this was coming from,   considering we have over 500 sites on the server, we expected to be   moonlighting for some time. However, with SSH access still, we ran a   command to find all files edited or created in the time the attacks   started. Luckily, the offending file was created over the winter   holidays which meant that not many other files were created on the   server at that time.      We were then able to identify the offending file which was inside the   uploaded images folder within a  website.      After a short cigarette break we concluded that, due to the files   location, it must have been uploaded via a file upload facility that   was inadequetly secured. After some googling, we found that there was   a security vulnerability that allowed files to be uploaded, within the   ZenCart admin panel, for a picture for a record company. (The section   that it never really even used), posting this form just uploaded any   file, it did not check the extension of the file, and didn't even   check to see if the user was logged in.      This meant that any files could be uploaded, including a PHP file for   the attack. We secured the vulnerability with ZenCart on the infected   site, and removed the offending files.      The job was done, and I was home for 2 a.m.            The Moral   - Always apply security patches for ZenCart, or any other CMS system for that matter. As when security updates are released, the whole   world is made aware of the vulnerability.   - Always do backups, and backup your backups.   - Employ or arrange for someone that will be there in times like these. To prevent anyone from relying on a panicy post on Server   Fault.


What information does Hidden State and Cell State carry? Do they carry the summary of the input sequence or what?

LSTM cells consist of two types of states, the cell state and hidden state. How do cell and hidden states differ, in terms of their functionality? What information do they carry?


What's the difference between "cited in" and "cited after" e.g. (cited in Hofstadter 1969: 10) and (cited after Manin 1997: 3)

I don't understand what's the meaning of "cited after" in books, when they cite a source, e.g.,       (cited after Manin 1997: 3)


I am using QGIS. I have two exports of vector data created some 6 months apart. How do I find any new objects added in the 6 months, and any attribute changes in the original objects? An asset_id field exists in both tables as a unique identifier, and will carry through both tables. I can use the "Difference" tool to get geometry changes but can't get the attribute table changes too.

I am using different shapefiles from open data in Switzerland. They have just updated the whole set. My question is: how to compared two layers (new and old version)? I would like to know the differences in geometry, as well as attributes. In the data there are points, lines and polygons and some of the sets contains a big amount of features (more than 300 000 elements). I have already checked all the simillar questions, but they all focus on creating the third layer with differences or particular layer example. What I want to know is just what has been changed. I am working with QGIS 2.14.3 and i am familiar with Python.


Assuming you have classes like Player, Enemy, Map and Tile.  The first approach to structuring rendering code would be to give each a render() method and let it draw itself:  void render(){    player.draw();    enemy.draw();    // etc. }   But considering the  perspective, that feels wrong... Another idea would be to make a Renderer class, but then I wonder how you give the Renderer information what to draw.  Which one should I choose and why?

I am very new to game development, but not to programming.  I am (again) playing around with a Pong type game using JavaScript's canvas element.  I have created a Paddle object which has the following properties...   width height x y colour   I also have a Pong object which has properties such as...   width height backgroundColour draw().   The draw() method currently is resetting the canvas and that is where a question came up.  Should the Paddle object have a draw() method responsible for its drawing, or should the draw() of the Pong object be responsible for drawing its actors (I assume that is the correct term, please correct me if I'm incorrect).  I figured that it would be advantagous for the Paddle to draw itself, as I instantiate two objects, Player and Enemy. If it were not in the Pong's draw(), I'd need to write similar code twice.  What is the best practice here?  Thanks.


Using the command directly works: $ find \ /home...  But not as alias: alias synclinks="find \        /home/foo/Pictures/ \        -type f -exec file --mime-type {} \+ | \        awk -F: '{if ($2 ~/image\//) print $1}' \        | xargs ln -t /home/foo/MyHardlinks"  $ synclinks  Returns awk: cmd. line:1: {if ( ~/image\//) print } awk: cmd. line:1:       ^ syntax error ln: missing file operand Try 'ln --help' for more information. find: ‘file’ terminated by signal 13 find: ‘file’ terminated by signal 13 find: ‘file’ terminated by signal 13 find: ‘file’ terminated by signal 13

Following on from  about stripping newlines out of text, I want to turn this into a zsh alias as follows:  alias striplines=' awk " /^$/ {print \"\n\"; } /./ {printf( \" %s \",$0);}"'   I've tried escaping the quotes inside the awk script, but I'm getting this error:  awk: (FILENAME=bspsrobustness FNR=1) fatal: division by zero attempted   (The file is called bspsrobustness)  Is there a way to do what I want? I suppose I could turn this into an awk script rather than a zsh alias, is that my best option?


I'm a native English speaker and I consider myself to have a very competent understanding of English grammar.  Recently, I have started believing that there is no future tense in English grammar.  Here are some examples of sentences that I previously believed were future tense, but now believe are either present tense or invalid (broken) English grammar:     I will do my homework tomorrow.    I say that this is present tense. The full (uncontracted) sentence is      I (have the/a) will to do my homework tomorrow.    Strictly, this sentence refers to the writer's will in the present. The usage seems to have been contracted in recent centuries, but "will" remains a noun and this seems to be the only grammatically-valid interpretation of this sentence.     I am going to the bathroom.    I say that this is present tense.  The only valid interpretation of this sentence is that the speaker is currently going to the bathroom (in the present, right now). Whether "going to the bathroom" means traveling to a bathroom or peeing in their pants is open to interpretation, but this does not affect the tense. The tense is determined by "am", so the tense is present.     I am going to school tomorrow.    I say this is invalid English grammar.  This is as invalid as I am going to school yesterday. The tense is present because of "am", and the sentence can not be validly interpreted as it stands.  In examples such as      We are going to Italy in Spring,    this is invalid for the same reason as above: "are" determines that the tense is present, and then a non-present time period is appended. This is as invalid as      We are going to Italy two years ago.   These are just a couple of examples but I have looked at many examples of future tense usage and I do not believe there is a valid future tense in English grammar.  Question: Is it true that English has no future tense?

According to A Student's Introduction to English Grammar, Tense is defined as follows:     Tense. A system marked by verb inflection or auxiliaries whose basic use to locate the situation in time: I liked it (past tense, past time), I like it(present tense, present time).   However, the author also points out:     ..., English is not one of them: it has no future tense. It does have several ways of talking about future time, and the most basic one does involve the auxiliary will.   These two quotes made me puzzled because, as noted above, Tense is denoted by inflection or auxiliaries and the auxiliary will seems to clearly meet the criteria. In conclusion, my question is   Why doesn't the auxiliary will qualify as future tense?


It is said that since work is done by the gravitational potential itself , so at a finite distance the gravitational potential energy of the body is negative. Could someone explain why?

Gravitational potential at a point in a gravitational field is defined as work done per unit mass in bringing a small test mass from infinity to the point.  I know that:   By integration, we find that gravitation potential is negative. The maximum value of gravitational potential which is at infinity distance is 0, therefore minimum value should be negative.   But, what I do not understand is force is in the same direction as displacement so why work done is not positive?


i am trying to feature to line conversion  that are not multipart lines and Merge output feature class but its loses the attributes.  Here is my code:  arcpy.env.workspace="in_memory/"  with arcpy.da.SearchCursor(LINEFEATURECLASS,['shape@']) as sip:     i=0     for row in sip:            geom=row[0]            if not geom.isMultipart:               op="polyLine"+str(i)             arcpy.FeatureToLine_management(geom,op,"0.001 Meters","ATTRIBUTES")                                   i=i+1     fclist=arcpy.ListFeatureClasses("","Polyline")     Merge=arcpy.Merge_management(fclist,"D://Merge_Polyline")    Tool working but it losing attributes.

My script takes separate 3D feature classes, calculates a field, appends to a target feature class, and then deletes the originals. This is a huge data processing task of over 4700 mass point feature classes appending to a single one. I know it was a big mistake to put so many feature classes into SDE, but given they're in there now, I've got to deal with them there (yes, the sheer fc count is bringing SDE performance to its knees--hence my urgency).  Early on it worked great, in that the merged result showed valid z-values. I was able to build a terrain and it looked great. I'd been running this in the background for weeks, and have just noticed z-values of 0 in the output, where the originals were not 0! Oh no!!! I'm certainly glad I still have the file-based originals!  Pseudocode:     An in_memory feature class is created from a z-aware template      For each fc in the feature dataset:            It is appended to the empty in_memory fc          The TILE_ID field is calculated using a portion of the name of the source fc           It is then appended to the target SDE fc          The in_memory feature class is emptied          Each processed fc is then deleted     When I initially posted, I was curious if it was my use of in_memory that caused this trouble. I had not initially been using it, and only switched to it because performance was far too slow otherwise, and WAY faster in_memory. To find where trouble started, I ran the Add XY Coordinates tool, which proved the trouble started with in_memory use. At that time I had also switched from CalculateField_management to da.UpdateCursor, so that's likely the bigger reason for the performance enhancement. I will now change my code to avoid in_memory.


Usually, when I start to create a list of things in a web application, I start by displaying a table  ╭───╥────────────┬─────────────╮ │   ║  Name      │   Email     │ ╞═══╬════════════╪═════════════╡ │ 1 ║ First      │ a@b.ux      │ │ 2 ║ Lorem      │ ipsum       │ └───╨────────────┴─────────────┘   Then the web app grows and I need to display more things:  ╭───╥────────────┬─────────────┬─────────────┬─────────────╮ │   ║  Name      │   Email     │   etc.      │   etc2.     │ ╞═══╬════════════╪═════════════╪═════════════╪═════════════╡ │ 1 ║ First      │ a@b.ux      │Lorem        │ ipsum       │ │ 2 ║ Lorem      │ ipsum       │Lorem        │ ipsum       │ └───╨────────────┴─────────────┴─────────────┴─────────────┘   Then it start to become unreadable, because there are too many columns.  Assuming all of these fields/properties are important (I mean, they have to be displayed in the list), what can I do to display all this information ?  Example of properties: name, firstname, email, group, departement, role, last connected at, action, ...  DISCLAIMER: I'm not a UX designer. And it may be my first question here: I can edit if I misunderstood some rules about UX questions.

What if you have too many columns in a table?   Possible solutions:   Horizontal scroll bar Re-sizable columns Table settings to filter out some columns   What is good/bad practice? Is there any other, more preferable, solutions to this problem?


I've organised unofficial SOru event several month ago: . I've wanted to print SOru logo on T-shirts and give them to members, but CM told me that SO is against it. We periodically receive questions on our meta about SE merchandise. (e.g. ). Our 100k user still  (almost a year passed).    People, at least, want to print SE logo by themself.  So:   Can members print the SE logo by themself? If yes, could you provide high-resolution images?

I happened to notice while on the Super User site that one user's picture shows him wearing a shirt with the Super User logo on it. Interested, I wanted to find out where he got it from. Looking through old questions on Meta, I found out that there used to be a shop.stackexchange.com site that sold Stack Exchange gear. Unfortunately, they no longer sell any merchandise.  Is there any site where I can purchase a Stack Exchange site shirt/hat/etc.? If not, could I create a shirt/hat/etc. myself with one of the sites' logos on it? If so, where can I locate the logos in their largest size?


I am looking at a situation where many people are wearing the look and I don't know for sure which one to use between these two:  They had all gathered in the ante-room, wearing a sombre look. They had all gathered in the ante-room, wearing sombre looks.  Also, is the comma necessary?

In a situation where say a group (or at least a plurality) of men is being addressed — for example on a sign passed by many married men — which is correct?  "Remind your wife."  or  "Remind your wives."


In the phrase Can't afford to spend any more time, I am not sure if I need a space between any and more.  I have checked two sources including  and . They suggest the following:        Any more is A determiner   It is similar to some more and describes an indefinite quantity of something.          Example:   Would you like any more tea?   Anymore =  adverb It means 'no longer' or 'in the past, but not now'     Example:   The cost of electricity is not cheap anymore.   So, in the phrase, Can't afford to spend any more time, which would you use?  There is an indefinite quantity of time, so based on the examples above it would be 'any more'. But then, the phrase also implies that they had time in the past but no longer, so does that mean it would be 'anymore'?  Also, does it make a difference if you are using American or British English, as the Cambridge link kind of suggests that anymore applies more to American English?

any more requests anymore requests  Are these two the same? It seems that "any more requests" is grammatically correct while "anymore requests" is not. Am I right? Why are they different?


My HDD is on its verge of death and I have Windows 8 installed on it. I have some pretty important files there that I need to take to the Ubuntu side. My Ubuntu installation is on its separate physical hard drive.  When I click one of my Windows 8 partitions via Ubuntu (there are two), I get this error message:  Error mounting /dev/sdb1 at /media/dugi/Store: Command-line `mount -t "ntfs" -o "uhelper=udisks2,nodev,nosuid,uid=1000,gid=1000,dmask=0077,fmask=0177" "/dev/sdb1" "/media/dugi/Store"' exited with non-zero exit status 14:    The disk contains an unclean file system (0, 0). Metadata kept in   Windows cache, refused to mount. Failed to mount '/dev/sdb1':   Operation not permitted The NTFS partition is in an unsafe state.   Please resume and shutdown Windows fully (no hibernation or fast   restarting), or mount the volume read-only with the 'ro' mount option.   Is there a way I can fix or backup my important data from this HDD via Ubuntu? It's the only way I have direct access to these HDDs - the Windows 8 system wont boot anymore.  Help would be appreciated.

Whenever I boot Ubuntu, I get a message that it cannot mount my windows partition, and I can choose to either wait, skip or manually mount.  When I try to enter my Windows partition through Nautilus I get a message saying that this partition is hibernated and that I need to enter the file system and properly close it, something I have done with no problem so I don't know why this happens.    Here's my partition table, if any more data is needed please let me know.     Device Boot      Start         End      Blocks   Id  System /dev/sda1            2048    20000767     9999360   83  Linux /dev/sda2        20002814   478001151   228999169    5  Extended /dev/sda3   *   478001152   622532607    72265728    7  HPFS/NTFS/exFAT /dev/sda4       622532608   625141759     1304576   82  Linux swap / Solaris /dev/sda5        20002816   478001151   228999168   83  Linux


I'm stuck on a detail in the proof of the following:  Let $R$ be a commutative ring with $1\neq 0$. Prove that if every proper ideal of $R$ is prime, then $R$ is a field.  Since $0 \neq 1$ we have that $\{0 \}$ is a proper ideal of $R$.  Further, $R$ is an integral domain since if $a\cdot b \in \{0\}$, then either $a=0$ or $b=0$ as $\{0\}$ is prime.  Now I would like to prove that $\{0\}$ is the only proper ideal of $R$ which would imply that $\{0\}$ is maximal and $F/\{0\} \cong F$ is a field.  My idea is that if $A,B \subseteq R$ are two proper ideals then it must be that $A = B$, and therefore any proper ideal of $R$ is $\{0\}$.  Notice that $AB \subseteq B$ so that $AB$ is also a proper ideal of $R$.  Since $AB \subseteq AB$, and $AB$ is prime, we have that either $A \subseteq AB \subseteq A$ or $B \subseteq AB \subseteq B$, which implies that either that $B = AB \subseteq A$ or $A = AB \subseteq B$.  Say $B = AB \subseteq A$.  I'm now stuck trying to show that $A \subseteq B$.    Is there a better way to do this?  I have also tried picking $r \in R\setminus\{0\}$, and showing that $r^{-1} \in R$ without success.

Let $R$ be a commutative ring with $1$. Suppose that all ideals $I \neq R$ are prime. Prove that $R$ is a field.   Help me some hints.  Thanks a lot.


I have a function that changes a table in a list, so far so good, but when the function changes in js it stops working, if I reload the page it works but if I change the DOM nothing. Can you help me?  $(document).ready(function() {     $('#table-list tbody tr').click(function(event) {         if(event.target.type == 'checkbox'){         }else{             $(':checkbox', this).trigger('click');         }     });      $('#ul-list li').click(function(event) {         var checkbox_type = $(event.target).find("input[type='checkbox']").attr('name');         if(checkbox_type){             $(':checkbox', this).trigger('click');         }     });  });   These are the two events that should always be active. But if I change the table to ul not it works  So let me explain better, I have a table like this:

       <input type="checkbox" name="1" />

       <input type="checkbox" name="3" />

   Then by clicking on a button I convert it to a list by removing the table from the DOM and inserting this:

       <input type="checkbox" name="1" />

       <input type="checkbox" name="3" />

   Now I want if I try to click on the list this function should start:  $('#ul-list li').click(function(event) {         var checkbox_type = $(event.target).find("input[type='checkbox']").attr('name');         if(checkbox_type){             $(':checkbox', this).trigger('click');         }     });   instead no.

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.


Which one is correct to speak? Why?   I will call you. I would call you.   What is the difference between the two? Thanks.

What is the difference between would and will in the following examples?        How would you use this word in a sentence?     How will you use this word in a sentence?


Here in this code, the fourth line(print(i)) is a little bit confusing. When I print it, I am getting the value of 10. Can someone explain what actually happened? def ranges2():     for i in [1, 3, 5, 7, 9, 10]:         print(i, ":", i ** 3)     print(i)  ranges2()  #result is 10................ why?🤔 ranges2()

What exactly are the Python scoping rules?  If I have some code:  code1 class Foo:    code2    def spam.....       code3       for code4..:        code5        x()   Where is x found?  Some possible choices include the list below:   In the enclosing source file In the class namespace In the function definition In the for loop index variable Inside the for loop   Also there is the context during execution, when the function spam is passed somewhere else. And maybe  pass a bit differently?  There must be a simple reference or algorithm somewhere.  It's a confusing world for intermediate Python programmers.


I am travelling to London from Delhi in next 8 hours (and then to Schengen countries) and I need some quick help in confirming my understanding of the visa type-C single entry Etats Schengen.  And I have a valid UK multiple entry visa also.  I am flying by British Airways as below with itinerary spread across next some days.  Delhi - London London - Gothenburg Gothenburg - Paris (but the flight will go back to London and then proceed to Paris) Paris - London London - Delhi    Now I understand that I can enter the Schengen area only once through any Schengen country and once I exit Schengen area through any country, I can't re-enter with same visa.  This being the case, will my travel from Gothenburg to Paris (via connecting flight through London) be called as exiting the Schengen area since I will be going to Paris via London?  Essentially, will there be a round of immigration pass through when I will travel from Gothenburg to Paris via London?

I have a single entry visa to Schengen countries(type c). I will be traveling to Norway from Toronto, Canada. I will stay for a week, then I will travel to Germany. My flight from Norway to Germany will have a transit in London. Will this be a problem with my Single Entry Visa? Will I be able to enter Germany even if I have a transit in London?


I'm working with a linear regression model given by the following formula $$y = \beta_1x + \beta_0 + \epsilon.$$ I am to prove that the correlation coefficient between $\hat{y}$ and $\epsilon$ is equal to zero if the model is correct. Basically this problem comes down to prove that $Cov(\hat{y}, \epsilon) = 0$. I'm a bit stuck here. I would appreciate any help.

In class we've seen that $a$ (the weights) must satisfy $$X^T (y-Xa) =0$$  Here $X$ is a $(n\times d)$ matrix (so we have $n$ samples in $\mathbb R^d$)  let's denote the residuals $r = y-Xa$. In our class notes, it is written that     The normal equations require the residuals to be orthogonal to each of the columns of $X$.   Why?     Therefore, the solution of the linear regression is a projection of $y$ onto the subspace spanned by $v_1 , \ldots , v_d$ (the columns of $X$)   Can you please explain this?


So yesterday I took paper and pencil and did some constructions of geometrical nature and I discovered a sequence that should converge to $\pi$.  It goes like this:     Define $a_1=\sqrt{2}$ and for every other $n \in \mathbb N$ define $a_n=\sqrt{2+a_{n-1}}$. Define $S_n=2^n \cdot \sqrt{2-a_{n-1}}$. Then we should have $\lim_{n \to \infty}S_n=\pi$.   This formula (more correctly, sequence) can be seen  and is labeled with number (66) so I did not discover anything new.  I found this sequence but I did not rigorously prove that it converges to $\pi$, the story is that I saw a pattern for the first few natural numbers and then defined the expression for general $n$ and when I did that I found the sequence on the above linked page.  My question would be:     In which way would you prove that this sequence converges to $\pi$?

Wikipedia claims this but only cites an offline proof:  $$\lim_{n\to\infty} 2^n \sqrt{2-\sqrt{2+\cdots+ \sqrt 2}} = \pi$$  for $n$ square roots and one minus sign. The formula is not the "usual" one, like Taylor series or something like that, so I can't easily prove it. I wrote a little script to calculate it and it's clearly visible, but that's not a proof.


I am trying to remove __v in every array element. How can I iterate through this array while removing the __v value from each element?  This is how my array looks like:      [     {         "itemName": "SDGSGEDEDW",         "description": "No description found",         "_id": "5d97e155976e7e145476298b",         "itemCode": "JFDQEKDEDQCGD",         "untiPrice": 23.23,         "vendor": "5d97e97177882e5b886fe32a",         "dateAdded": "2019-10-05T00:18:29.128Z",         "__v": 0 //want to remove this     },     {         "itemName": "SDGSGEDEDW",         "description": "No description found",         "_id": "5d97e2e7d7a4b12dd800bca6",         "itemCode": "JFDQEKDEDQCGD",         "untiPrice": 23.23,         "vendor": "5d97ea3177882e5b886fe330",         "dateAdded": "2019-10-05T00:25:11.665Z",         "__v": 0 //want to remove this     } ]   So after removing the final array would should look like this:  [     {         "itemName": "SDGSGEDEDW",         "description": "No description found",         "_id": "5d97e155976e7e145476298b",         "itemCode": "JFDQEKDEDQCGD",         "untiPrice": 23.23,         "vendor": "5d97e97177882e5b886fe32a",         "dateAdded": "2019-10-05T00:18:29.128Z"     },     {         "itemName": "SDGSGEDEDW",         "description": "No description found",         "_id": "5d97e2e7d7a4b12dd800bca6",         "itemCode": "JFDQEKDEDQCGD",         "untiPrice": 23.23,         "vendor": "5d97ea3177882e5b886fe330",         "dateAdded": "2019-10-05T00:25:11.665Z"     } ]   Here what I was trying but it is not working:  arr.filter((item) => {           return item.__v !== 0 });   How can I do this?

Say I create an object as follows: let myObject = {   "ircEvent": "PRIVMSG",   "method": "newURI",   "regex": "^http://.*" };  How should I remove the property regex to end up with new myObject as follows? let myObject = {   "ircEvent": "PRIVMSG",   "method": "newURI" };


Let $A$ be the set $\{\propto,\{1,\propto\},\{3\},\{\{1,3\}\},3\}$.   The statement "$\{1,\propto\}\subseteq A$" is false.   (Taken from )  But I think this is true as can see $\{1,\propto\}$ as being a subset of $A$ ?

I am trying to make sense of these. To me a is false because the set isn't empty. Is that correct? b is true because the empty set is an element of that set. c is false because the set the empty set isn't an element, it is a subset or proper subset. d is true because the set the empty set is a member of that set. e the set the empty set is false because it is not a proper subset I think f false for the same reason g false for the same  a) ∅ ∈ {∅} b) ∅ ∈ {∅, {∅}} c) {∅} ∈ {∅} d) {∅} ∈ {{∅}} e) {∅} ⊂ {∅, {∅}} f ) {{∅}} ⊂ {∅, {∅}} g) {{∅}} ⊂ {{∅}, {∅}}  I know not all these are correct, why is my logic wrong?


Let $f:(0,\infty)\to \Bbb R$ be a twice differentiable function. In  answer, it is asserted that the MVT lets one write $$f(x+h)=f(x)+f'(x)h+\frac12 f''(\xi)h^2$$ for some $\xi\in (x,x+h)$.  It is not clear to me why this should be the case. Using the MVT, one can write $f''(\xi)h=f'(x+h)-f'(x)$ for some $\xi\in (x,x+h)$. Using that, the claim rephrases to $$f(x+h)=f(x)+\frac{1}{2}f'(x)h+\frac{1}{2}f'(x+h)h$$ and I don't see why that should hold.  I'm sure I'm being stupid, therefore I much welcome clarification.

I am trying to prove there is a $c \in (a,b)$ such that $$ f(b)=f(a)+f'(a)(b-a)+ \frac{1}{2} f''(c)(b-a)^2 $$  which I do believe is a specialized form of the Taylor's Theorem when you plug in $b$ and $a$ into the appropriate spots.  I think you can approach this by proving the Lagrangian remainder is the same, but it doesn't seem all that intuitive.


Do all windows applications work in ubuntu with wine? Can I use Microsoft office in ubuntu using wine application.

How can I get playonlinux to install Microsoft Office 2016. The options from the install menu only go up to 2013.   Is there a more recent version of PlayOnLinux (or indeed Wine) I can download to enable installation of MS Office 2016?  The steps I take are:   open PlayOnLinux  click Install Click Office returns a list of several software packages including MS Office 2007, 2010 and 2013 (but alas not 2016)


Sky looks blue because because our eyes are sensitive to blue colour. But when viewed through a camera why don't we see violet of the sky even though we can see violet colour of other pictures taken from the camera?

I realise the question of why this sky is blue is considered reasonably often here, one way or another.  You can take that knowledge as given.  What I'm wondering is, given that the spectrum of Rayleigh scattering goes like $\omega^4$, why is the sky not purple, rather than blue?    I think this is a reasonable question because  (or, strictly, violet or indigo) in rainbows, so why not across the whole sky if that's the strongest part of the spectrum?  There are two possible lines of argument I've  and I'm not sure which (if not both) is correct.  Firstly, the Sun's thermal emission peaks in the visible range, so we do actually receive less purple than blue. Secondly, the receptor's in our eye are balanced so that we are most sensitive to (roughly) .  Our eyes are simply less sensitive to the purple light than to the blue.


I know I can see my total count of votes, but I'd be interested in having these be part of my activity tab, so I can easily revisit questions. I end up favoriting almost every question I upvote, just so I have a way to go back to it.

Yesterday, I voted to close a question as a duplicate. Today, I'm curious if the question is still open, but I did not keep a link to that question.  Is there some way to see a list or history of questions that I voted to close? On my activity tab, I can only find "reviews", which does not include questions that I vote on outside of reviews.


I just want to append a scene (named "fred" which is the ONLY scene in the file) to the existing open blend file. Seems like this should be easy, but I can't find out how to do this. So, after the append there should be two scenes: the orignal one and a new one named "fred".  I know the name and location of the file and the scene I want appended.  Thanks for any help.

I'm searching a way to append a group in Python.  It should behave exactly like the Append function (ShiftF1) works, all objects should be local and editable. The idea is to append a character (with rig etc.) via Python and not Link it (to be able to modify it without making everything local one by one).  Thanks


It seems to me that the subject category comprehends not only "understanding of the problem" but also "effort to solve". These both seem like valid reasons to close, but it seems odd to bundle them and even odder to bundle them under a bold-formatted name (i.e. minimum understanding of the problem) that comprehends only one element.  The situation is further muddied by the fact that people seem to also use this category for situations where they feel the poster has not demonstrated sufficient competence in their efforts to solve the problem.  Perhaps the people who wrote this category are thinking of "problem" in the broader sense of "problem and the associated solution space"?  In any event, my question is whether this category (including the bolding) should:   Remain as is? Be reworded/rebolded to more accurately reflect the existing scope? Be otherwise refactored?   Update in response to close votes: This question is different than  because the latter only addresses the question of emphasis/bolding whereas this question raises questions of wording/semantics and whether to refactor the category (e.g. split out some of the content into other categories).  For example, this question also covers:   What is meant by "problem" in the phrase "understanding the problem"? Does it refer to just surface level symptoms, what's causing the symptoms, what's required to address the cause? Should we use more specific language?emphasized text Which, if any, of these things is really a requirement given the de facto standard or what is acceptable on SO, where one or more of these things is commonly absent in unclosed questions. Should demonstrated understanding/competence in the solution space be in a separate category from demonstrated understanding of the symptoms and/or causes of those symptoms (i.e. what I would consider "the problem")?

Call me nitpicky, but I can't ignore the fact that the emphasis on the following close reason is misleading:     Questions asking for code must demonstrate a minimal understanding   of the problem being solved. Include attempted solutions, why they   didn't work, and the expected results. See also:    (Emphasis not mine)   The main emphasis is about what they did wrong, rather than how to fix it!       demonstrate a minimal understanding of the problem being solved   So the OP thinks     What does that supposed to mean? I know what my problem is!   Instead, the emphasis should be on Include attempted solutions, why they didn't work, and the expected results Also, the emphasis is set on the expected results, rather than what's usually missing from the question, the attempted solutions.     I suggest the following emphasis:     Questions asking for code must demonstrate a minimal understanding   of the problem being solved. Include attempted solutions, why they   didn't work, and the expected results. See also:


β′xi+ (ρσ)(ϕ(α′zi))/(Φ(α′zi)) ............How this has come, especially the numerator part (ρσ)(ϕ(α′zi)? Could you explain in a simple and lucid way? Also, if you could provide proof step by step with proper explanation.

Say I have two independent random variables $X \sim N(u_1, \sigma_1)$ and $Y \sim N(u_2, \sigma_2)$. I want to get the conditional distribution of X given whether X is bigger than Y or not.  $P(X|X<Y)$ = ... and  $P(X|X>Y)$ = ...  I am thinking solving this in this way:  \begin{align} P(X|X<Y) &= \frac{P(Y>X|X)P(X)}{P(Y>X)} \\ &= \frac{(1-\Phi(\frac{x-\mu_2}{\sigma_2}))N(\mu_1,\sigma_1)}{\Phi(\frac{\mu_2-\mu_1}{\sqrt{\sigma_2^2+\sigma_1^2}})}\\ P(X|X>Y) &= \frac{P(Y<X|X)P(X)}{P(Y<X)} \\ &= \frac{\Phi(\frac{x-\mu_2}{\sigma_2})N(\mu_1,\sigma_1)}{1-\Phi(\frac{\mu_2-\mu_1}{\sqrt{\sigma_2^2+\sigma_1^2}})} \end{align}  My questions are:   (1) Whether above solution is correct  (2) How to get the mean and sd for $P(X|X<Y)$ and $P(X|X>Y)$ if they are still normal?


What i need to do here is simple but for some reason i'm just drawing a blank on this and need some assurance on how to do it correctly.  I'm trying to determine the UTC equivalent of 5AM Pacific Time tomorrow. I'm trying to do this without relying on the server time as i have no way of knowing what time zone this is.  I just need a sanity check on the following. Is this the best way to do this? Am i going to run into issues with the server time being off? Is this going to give me a accurate representation of 5am tomorrow UTC?  DateTime datetime = new DateTime(DateTime.Now.Year, DateTime.Now.Month, DateTime.Now.AddDays(1).Day, 5, 0, 0); //5AM tomorrow TimeZoneInfo pstZone = TimeZoneInfo.FindSystemTimeZoneById("Pacific Standard Time"); DateTime pstTime = TimeZoneInfo.ConvertTimeToUtc(datetime, pstZone);   TIA

I'm trying to create a unit test to test the case for when the timezone changes on a machine because it has been incorrectly set and then corrected.  In the test I need to be able to create DateTime objects in a none local time zone to ensure that people running the test can do so successfully irrespective of where they are located.  From what I can see from the DateTime constructor I can set the TimeZone to be either the local timezone, the UTC timezone or not specified.  How do I create a DateTime with a specific timezone like PST?


I was trying to compile a document which includes the package . Unfortunately, it seems that the version of TeX Live which I have installed is too old. I can tell from the multiaudience documentation that v1.02 was released on the date 2015/08/02. The output of running pdflatex shows that my LaTeX2e version is dated 2015/01/01.  Here is a MWE.  \documentclass{beamer}  \usepackage{multiaudience}  \begin{document}  \begin{frame}{Student slide 1} blah blah blah \end{frame}  \end{document}   And here is the output from compiling it the document.  $ pdflatex main This is pdfTeX, Version 3.14159265-2.6-1.40.16 (TeX Live 2015 (preloaded format=pdflatex) restricted \write18 enabled. entering extended mode (./main.tex LaTeX2e <2015/01/01> patch level 2 Babel <3.9l> and hyphenation patterns for 79 languages loaded. ... ! LaTeX Error: File `multiaudience.sty' not found.  Type X to quit or <RETURN> to proceed, or enter new name. (Default extension: sty)   Is there a way to update my TeX Live packages?

I need to install a new TeX/LaTeX/ConTeXt package on my computer.  I'm running Ubuntu/Fedora/Slackware/Some-Version-Of Linux.  What are the possible ways to do this?    Note:   We get a number of questions that essentially reduce to this one; it was felt a good idea to have one question-and-answer that can cover all the standard methods.  See  for the discussion.  The question-and-answer are CW so that more information can be easily added.  If you have information to add, please do so.  If you are unsure, leave a comment here or (preferably) in .  Comments on the question and answer will be periodically removed to ensure that the information is clear.


My array is something like this:     $sth = array(         array("group" => "1", "name" => "John", "whatever" => "a"),         array("group" => "1", "name" => "John", "whatever" => "b"), // this is the duplicate I want to remove         array("group" => "1", "name" => "Henry", "whatever" => "c"),         array("group" => "2", "name" => "John", "whatever" => "d"),         array("group" => "2", "name" => "Peter", "whatever" => "e")     )   And I want to remove the duplicate 1/John entry, but not the 2/John since it's not a duplicate. I only want to check those two values, not the "whatever" value, since that will always be different. I know I could use in_array to search for just "John", or array_search to check the keys, but the keys don't always correlate to the name, so I need to only remove duplicates where the key/value are the exact same. I'm thinking something like:  $cleaned_sth = array(); foreach($sth as $s) {     $group = $s[0];     $name = $s[1];     if( in_array($group => $name, $cleaned_sth ) continue;     else $cleaned_sth[] = array("group" => $group, "name" => $name); }

How can I remove duplicate values from a multi-dimensional array in PHP?  Example array:  Array (     [0] => Array     (         [0] => abc         [1] => def     )      [1] => Array     (         [0] => ghi         [1] => jkl     )      [2] => Array     (         [0] => mno         [1] => pql     )      [3] => Array     (         [0] => abc         [1] => def     )      [4] => Array     (         [0] => ghi         [1] => jkl     )      [5] => Array     (         [0] => mno         [1] => pql     )  )


How to answer “who is singing over there?_____ is Ivan’s sister. A: She.   B: It.  C. That

With the enthusiastic question of "Who wants ice-cream?", what is the more correct response?         (Not) I.   (Not) me.      Neither response is a sentence. The first response of "(not) I" sounds stuffy, like it should be followed with an indignant sniff. The second sounds like American idiom and acceptable for casual speech.    What do you say?


I have some commands that take too long to execute so I need a bash script to execute them serially.  The commands:  cd ~/my_file  command 1  command 2 ... command n    This is on Ubuntu 18.04. How should I do it?

I was curious how I would go about running multiple commands via shell script.  For example, just to try it out, I'd like to be able to connect a .desktop to a .sh that will run all the update codes so I don't have to type it out. I know how to execute a single command via a .sh, not multiple.  Any way?


I have a windows 7 pc but ubuntu does not allow me to go to a normal windows screen so i want to remove ubuntu from my pc.

I have absolutely no experience with Linux, and I desperately need to get my computer back up and running again with Windows.  How do I remove Ubuntu and reinstall Windows?    Editor's note: many of the answers are about removing Ubuntu from dual-boot but keeping Windows (which is a bit complicated), while other answers are about removing Ubuntu from single-boot (which is easy: basically just format the disk while installing Windows). The question as written is ambiguous between dual-boot or single-boot.


This question it's diferent to   Obviously the server has a security commitment. But this question presents some specific and not generic issues, as generic and very obvious are those of the post which is accused of being a duplicate.  The special difference is that a series of data is provided, which refers to a specific question: sending mail if you use the sendmail system, a contribution of data regarding how the use of the server was detected for the mail, and The suspicions of how it is done.  If you want to mark this as a duplicate, then 99% of StackOverflow and its variants is a duplicate.  Affair:  On last day one of my machines is involved on campaign of sending spam with subject "Incomming voicemail" Supposedly sent by WhatsApp.  I know this beacuse my provideer detect spam sending of my server. Oops. My server use Exim, and ASSP how anti-spam system.  Well, my provider send me some examples of spam. Destination IP: 74.125.129.27 - Message-ID: 7eE1c2268c4.8E2eBB6d3b915f3dc69aacA1E36@fes.de - Spam score: 600 Destination IP: 74.125.129.27 - Message-ID: 5C6e3Cf89a.9E98A6E9af61F2C6aC3a214@frfsa.org - Spam score: 600 Destination IP: 74.125.129.27 - Message-ID: 9e2E3aA2EDd54C5AD52ae1.C23DC3e9faD3@clayton.com - Spam score: 600 Destination IP: 74.125.129.27 - Message-ID: Fd7521FAf5BC98C87.3BacFaAe@wapi.com - Spam score: 300 Destination IP: 74.125.129.27 - Message-ID: a87fa6d2Cb4Ab42A9f3e54859a84A8f152b6cc@masapon.net - Spam score: 600   On my server there is no evidence of such submissions. We talk about the exim logs and the ASSP logs, and we're talking about looking only at the destination domain.  To analyze the problem, create a script to create a dump with tcpdump on the port 25 traffic in order to verify and analyze if it was true that my provider was detecting those submissions.  When I analyze the traffic in the next suspension of traffic, I returned to find nothing in the logs but my surprise when analyzing with Wireshark the pcap file of the temporary space sent to the sending of spam, I found that all the evidence was there.  I do not understand how it is possible to send mail without it passing through the ASSP and Exim logs, unless you are using a program that does telnet?  An error or lack of configuration in ASSP or Exim?  On wireshark  220 SNT004-MC4F14.hotmail.com Sending unsolicited commercial or bulk e-mail to Microsoft's computer network is prohibited. Other restrictions are found at http://privacy.microsoft.com/en-us/anti-spam.mspx. Fri, 17 Feb 2017 16:51:25 -0800  HELO srv108.tamainut.net 250 SNT004-MC4F14.hotmail.com (3.22.0.27) Hello [176.31.31.233] MAIL FROM: <davidiqwq@clayton.com> 250 davidiqwq@clayton.com....Sender OK RCPT TO: <rdlord@msn.com> 550 Requested action not taken: mailbox unavailable

This is a  about Server Security - Responding to Breach Events (Hacking)   See Also:                  Canonical Version I suspect that one or more of my servers is compromised by a hacker, virus, or other mechanism:   What are my first steps? When I arrive on site should I disconnect the server, preserve "evidence", are there other initial considerations? How do I go about getting services back online? How do I prevent the same thing from happening immediately again? Are there best practices or methodologies for learning from this incident? If I wanted to put a Incident Response Plan together, where would I start? Should this be part of my Disaster Recovery or Business Continuity Planning?   Original Version       2011.01.02 - I'm on my way into work at 9.30 p.m. on a Sunday because our server has been compromised somehow and was resulting in a    attack on our provider. The servers access to the Internet   has been shut down which means over 5-600 of our clients sites are now   down. Now this could be an FTP hack, or some weakness in code   somewhere. I'm not sure till I get there.      How can I track this down quickly? We're in for a whole lot of   litigation if I don't get the server back up ASAP. Any help is   appreciated. We are running Open SUSE 11.0.            2011.01.03 - Thanks to everyone for your help. Luckily I WASN'T the only person responsible for this server, just the nearest. We managed   to resolve this problem, although it may not apply to many others in a   different situation. I'll detail what we did.      We unplugged the server from the net. It was performing (attempting to   perform) a Denial Of Service attack on another server in Indonesia,   and the guilty party was also based there.      We firstly tried to identify where on the server this was coming from,   considering we have over 500 sites on the server, we expected to be   moonlighting for some time. However, with SSH access still, we ran a   command to find all files edited or created in the time the attacks   started. Luckily, the offending file was created over the winter   holidays which meant that not many other files were created on the   server at that time.      We were then able to identify the offending file which was inside the   uploaded images folder within a  website.      After a short cigarette break we concluded that, due to the files   location, it must have been uploaded via a file upload facility that   was inadequetly secured. After some googling, we found that there was   a security vulnerability that allowed files to be uploaded, within the   ZenCart admin panel, for a picture for a record company. (The section   that it never really even used), posting this form just uploaded any   file, it did not check the extension of the file, and didn't even   check to see if the user was logged in.      This meant that any files could be uploaded, including a PHP file for   the attack. We secured the vulnerability with ZenCart on the infected   site, and removed the offending files.      The job was done, and I was home for 2 a.m.            The Moral   - Always apply security patches for ZenCart, or any other CMS system for that matter. As when security updates are released, the whole   world is made aware of the vulnerability.   - Always do backups, and backup your backups.   - Employ or arrange for someone that will be there in times like these. To prevent anyone from relying on a panicy post on Server   Fault.


How do I make permanent the changing of my /home folder  I changed the /home folder using this command:  sudo mount /dev/sda2 /home   It works fine but, when I restart, the change is lost.  ¿ How do I make it permanent  ?

I am using Ubuntu Minimal + LXDE. I am wondering how can I auto-mount a partition (internal) on boot automatically. Currently I do something like   mount /dev/sda3 /media/works   But I want it to be permanent. Also I have GParted, but the Partition > UnMount is greyed out (yes, unmount, even though I haven't mounted it)


Problem Evaluate $$x_n=\sqrt{1+2\sqrt{1+3\sqrt{1+\cdots}}}.$$ My Reaserch In fact, the problem requires to evaluate the limit of the sequence below as $n \to \infty$ $$x_n=\sqrt{1+2\sqrt{1+3\sqrt{1+\cdots+(n-2)\sqrt{1+(n-1)\sqrt{1+n}}}}},$$where $n=1,2,\cdots.$ We may show that the limit really exists by $\textbf{Monotone Convergence Theorem}$. First, it's clear that $x_n$ is increasing with the increasing $n$. Second, we may obtain$$\begin{align*}x_n&<\sqrt{1+2\sqrt{1+3\sqrt{1+\cdots+\sqrt{1+n\sqrt{(n+2)^2}}}}}\\&<\sqrt{1+2\sqrt{1+3\sqrt{1+\cdots+\sqrt{1+(n-1)(n+1)}}}}\\&=\cdots\\&=\sqrt{1+2 \times 4}\\&=3.\end{align*}$$ Hitherto,we have showed that $x_n$ is increasing but with an upper bound $3$. Therefore, there exists a limit for $x_n$ as $n \to \infty$. But how to go on with this? I'm stuck here.

How does one prove the following limit? $$   \lim_{n \to \infty}   \sqrt{1 + 2 \sqrt{1 + 3 \sqrt{1 + \cdots \sqrt{1 + (n - 1) \sqrt{1 + n}}}}} = 3. $$


I downloaded a specific layer which has the format "AIG" as you can see in the screenshot.      It has no projection so I applied "Define Projection" on it. I searched for the projection and found the following:     4.1 - INDIRECT SPATIAL REFERENCE SYSTEM:      Type of indirect spatial reference system:      By country.      Reference date:    2001.      4.2 - DIRECT SPATIAL REFERENCE SYSTEM:      Datum:  Lambert Azimuthal.      Ellipsoid: Sphere.      Map projection: Projection    LAMBERT_AZIMUTHAL      Units                    METERS              Spheroid         SPHERE      Major Axis        6378388.00000               Minor Axis       0.00000      Parameters:      radius of the sphere of reference                      6378388.00000      longitude of centre of projection                        9  0  0.000      latitude of centre of projection                        48  0  0.000      false easting (meters)                                       0.00000      false northing (meters)                                      0.00000   The problem I have is that if search for this projection I get these two    After applying the first one using "Define Projection", nothing changes in the file. By this I mean the spatial reference is still "undefined" and the coordinate system is unknown. I also tried other projections but nothing works. If I convert it to a polygon first, define projection works but the reference on the map is still completely wrong. I think these problems occur because of the "uncommon" raster format?  I also think that the projection from the screenshot is not equal to the one I posted up here?  My goal is to project it in the end to "British National Grid" as all my layers I work with have this projection.  I also tried it on another computer with ArcGIs 10.2 and the same problem occured.  See these FME links for further reference to the AIG format:          I am using ArcGIS 10.2.2 for Desktop.

I have a Shapefile but its coordinate system is Unknown, and there is no *.prj file.   How can I identify it now?


I reinstalled Catalina and everything works just fine with installation. but I am stuck at here and the setup assistant doesn't show up after the installation.  I tried I Cloud account and I tried also the old user password

On my mac I have 2 accounts and the both are normal account. So in this moment I don't have a Administrator account, only one that was in the past a administrator, but now is not.  How I can have again a Administrator account?


I've got to type this symbol in my article. I've searched through Internet but haven't seen anything about how to write it in TeX command. It is perhaps rarely seen or used. But I really need to use it in my article:   And below are the packages I am using:  Can you help me? Best regards!

I know what my symbol or character looks like, but I don't know what the command is or which math alphabet it came from. How do I go about finding this out?


Let $B(x,r)$ be an open ball in $\mathbb R^n$ , then is the Lebesgue measure of the boundary of $B(x,r)$ zero ?

If $\mu$ is a Radon measure on $\mathbb{R}^n$ and $B_r$ is a closed ball of radius $r$. Why is $\mu(\partial B_r) = 0$? Or how can I prove that there is at least one $r_0 > 0$ such that $\mu(\partial B_{r_0}) = 0$?


I have a   VM guest, which I run in vboxHeadless mode. The host is Linux 64-bit. The VirtualBox version is 4.2.12r84980.  The VM loads fine, and I am presented with the "windows server" greeting screen. That is, I have to press Alt + Ctrl + Del to log on.  I have tried numerous ways to send Alt + Ctrl + Del:   Remote desktop to the VM from the port that is assigned by VirtualBox headless. That is, <VirtualBox host IP address>: VMguestPort. A-C-D doesn't work as the key sequence gets intercepted by the client PC at which I'm sitting and trying to log on to the VM guest. Remote desktop directly to the VM <Windows Server 2008 VM guest IP address>:3389 doesn't work for the same reason.  gives an a button to send A-C-D to a VM guest. This doesn't work either. I read that from a command line I could use the command  VBoxManage controlvm win2k8_64 keyboardputscancode 1d 38 53  VBoxManage controlvm win2k8_64 keyboardputscancode 9D B8 D3    for key press and then key release sequence. This doesn't work either.  Why do these work? Especially with a Windows Server 2008 as a VM guest?    The suggested previous answer does not work (pressing Alt + Ctrl + End does not work either) and also, as I am running a headless server, there isn't any change for me to see the VirtualBox GUI. The best I can get is the phpVirtualBox web interface and in VirtualBox there isn't any "right Ctrl" capture key.

I'm running VirtualBox with Windows Vista as host OS and Windows Server 2008 as guest OS. To login to Windows Server I have to press Ctrl+Alt+Delete, but my host OS reacts on that so I can not send it to VirtualBox. How can I do it?


I have about 16 photos of teammates standing in front of a green screen. I have to remove all the green obviously, usually, I do this with the magic wand tool but what is the best/cleanest way to do it?  Any good tutorials out there?

How can I green screen in Photoshop? I am making a picture were I need to green screen, and it would be very helpful if someone could help me!


The book starts out with human space explorers coming across very tall humans that left earth around a thousand years earlier. Turns out, the tall humans are descended from knights that charged an alien spaceship that landed on earth.  The knights end up conquering the aliens by laying siege to their cities and converting them to Christianity.

I'm searching for a science-fiction book set in the quite an old time: around the 15th-16th century. Features aliens arriving in a spaceship to an old country: likely a western country from what I remember.  Here are the details that I can remember:   Read the book during 2005-2008. Definitely not published during that time based on the writing style: I will hazard a guess at around 1960-1980 publication.  Story begins where there's some sort of military rally and an alien spaceship lands in this old country. The aliens attempt to kill the people there but are overpowered and killed. I believe 1-2 aliens were kept as prisoners. People board (capture) the ship and use it to travel to the alien's base seemingly reach there. They talk to the aliens and have a treaty whereby the aliens also have to serve in the (people's) country's military force to win a war.  Not long after one of the alien's bases are bombed and the spaceship is destroyed, leaving the people trapped on the alien's country.    I'm pretty sure the ending is where a few years later, the people trapped on that planet manage to get back home.   One interesting part to note: when the people captured the spaceship they named it. I can't remember the name but it likely has an '-ade' at the back. Something like 'Invade' along the line.   I just remembered reading the book recently after reading 'War of the Worlds' - another alien scifi book; any help is appreciated!


What's with this Adobe logo? I don't use Adobe Flex, I use Flex, the fast lexer, and I've had to add a million tags to my ignored list to try (unsuccessfully) to filter out the questions about this Adobe Flex business to get to the (few) questions about Lex and Yacc. And now this?  I suppose this is some kind of promotion sponsored by Adobe. How long will it last? When can I go back to trying to forget that a company I don't like has a product with the same name as a common tool that helps write compilers?

What does an icon on the tag mean, for example the "rg" before the sql-server tag as pictured below?


$$\sum_{k=1}^{2015}(-1)^\frac{k(k+1)}{2}\times k$$   How to solve this. Answer provided is $0$

Find the sum $S=\sum_{k=1}^{2015}{(-1)^{\frac{k(k+1)}{2}}}k.$  I partitioned k in two categories Either k is congruent to 0 , 3 mod(4) or congruent to 1,2 mod(4). But still I didn't get answer


Can I take a photo with blurred background with Samsung s5 for a subject far by 2 metres of the lens? and what is the specific distance for manual focus for a 16 megapixel mobile phone lens to take a blurred background picture for someone ?

I have wondered how to get some parts of the image out of focus when using smartphone cameras (or if it can even be done). Recently found out about the concept of bokeh, and am interested in techniques to use it in image composition for cell phone cameras (the typical 8MP low aperture size digicams prevalent in recent Android devices).


for a 32bit/2GRAM Dell Laptop, i'll be required to download the Ubuntu 64bit or the 32bit   version? Looking forward for help, and thank's for the support!

What is the difference between 32-bit and 64-bit Ubuntu? I've heard the 64-bit platform performs better and can detect more than 4GB of RAM. Also, while some apps haven't ported to 64-bit yet, ia32-libs lets a 64-bit machine run them.  If so, why not promote 64-bit over 32-bit?


Hard links  Given a file original.txt, a hard link hardlink.txt will point to the same inode and continue to exist even when original.txt is deleted.  Symbolic links  Given a file original.txt, a symbolic link symlink.txt will point to the file name.  Question: Which one is faster and which one is smaller?  My intuition says that hard links would be faster, as they are indistinguishable from the original file. However, everything depends on the speed of symbolic links.  Also, which one takes up less hard disk space?  I would like to see answers based on measurements, as questions like  briefly mention size and speed, but do not detail it.

but why would I use them? What is the utility of a hard link?


This is really similar to  but some of the methods did not work for me. For example Clonezilla and GParted is not booting from my USB device (created with ).  I was following  but the the de-fragment process could not move the data to the disk so the shrink process ended shrinking 300GB (my ssd is 256GB and the data on the HDD is less than that).   Is there a BIOS option for booing Clonezilla or any other easy and clever way to clone my HDD? In worse case scenario I am planning to clean install to SSD without touching HDD. Is there any way to clone my restore partition to USB drive as a bootable device?

Is there a free way to clone a full Windows 7 installation from HDD to SSD? (The free part is important, I know I can pay for Acronis True Image.)      SSDs are usually much smaller than HDDs which complicates matters. For instance, I have about 50GB data, my new SSD is 80GB but I still can't use Windows clone/restore system if my HDD is something like 300GB.  Therefore, I'm looking for a third party tool that will be able to:   Create a clone of my C: partition Store it onto an external USB drive Boot from some rescue / restore CD Load the image onto the new SSD   Acronis True Image seems like a tool that should support this but it's a paid-for software and the trial version cannot create clones. Acronis Migrate Easy is a fully functional tria for 15 days but need both the HDD and SSD connected at the same time which is a bit of a problem for me as a laptop user.  P.S. I almost got there combining Windows image backup combined with Acronis True Image restore CD (which can load .vhd's) but was not able to boot as some boot information were probably lost and could not be repaired using the Win7 installation DVD.


<lightning:select name="levelrate" aura:id="recpickVal" class="level" label="Select Tier"  onchange="{!c.tierRateChange}">                         <option text="--Select--" value="NONE"/>                             <aura:iteration items="{!v.tierRates}" var="su">                              <option text="{!su.Tier__c}" value{!su.Charge_Rate__c}"/>                         </aura:iteration>                     </lightning:select>   Here in this code I am getting the value in controller by using var dataVal = event.getSource().get("v.value");  But here I also want the option text name in my controller.How can I get that. Any idea how can I get the option text name.

I would like to get the value of the label of the selected drop down item.  In this case, the label is the Name of the Contact.  <aura:component>  <aura:attribute name="contacts" type="Contact[]"/>  <lightning:select label="Contact" aura:id="contactList" name="contactList">     <aura:iteration items="{!v.contacts}" var="c" indexVar="index">        <option value="{!c.Id}">{!c.Name}</option>    </aura:iteration>  </lightning:select>  </aura:component>   I know how to get the value:  component.find("contactList").get("v.value");   But how do I get the label?


There was recently a featured question which about . On that question, there was one comment in particular which caught my attention.     Perhaps you could put the source for the t-shirt design on the back.   -   I initially misinterpreted wizz's comment, thinking that it was referring to a LaTeX formula which would display it's own source code.  Programs that output their own source code, , are not uncommon. You can find  of these over on . However, across all the quine challenges, I've never seen a LaTeX formula output it's own source code before.  Are there any examples of a LaTeX formula which draws its own source code?

Since TeX and LaTeX can print out any text, it should be possible to write a self-replicating document, i.e., a document that is typeset as a PDF/DVI of itself. Have you seen something like that?


Let's say I have a single secret with high entropy, S, for the entire application. I want to generate keys K1, K2 for 2 different users of the app. I run:  K1 = PBKDF2(S, salt1) K2 = PBKDF2(S, salt2)   where each salt is some 128 bit random number.   Is this a safe construction or do KDFs (or PBKDF2 specifically) have any properties that user 1, knowing K1, could infer any part of K2?  EDIT:  Assume a non-broken hash and a sufficient number of iterations for the KDF

I'm designing a scheme for management of a small number of cryptographic keys (< 100 at any given time) and I had an idea: rather than storing all the keys, could I just store one master key and use a KDF to derive the particular key I need by varying the salt in a certain way?   For example, if I need the second encryption key for usage X, I'd give something like PBKDF a salt of   $$2||“encryption”||X||<random value>$$  which would uniquely derive the second version of that particular key.


I've been recently talking with someone in the comments of my answer to his question on Stack Overflow, and he moved the discussion to the chat, for which I had to open my browser. Then I thought: Why don't we have the ability to chat inside the Stack Exchange app? Actually, not a bad thought, though. I also noticed, the "create chat" privilege is not showing up in the app, but in the web interface it does. Would like to see this added by the Developers.

It would be nice to have the ability to check in the chat rooms via chat. I personally would use this frequently if available, and I'm sure others out there would as well.


Thank you so much for your time. I am running an analysis where I explore the association of the same predictors across multiple outcomes (these outcomes are correlated). My understanding is that when I run this in R: lm.all <- lm(cbind(outcome1, outcome2, outcome3) ~ age + sex + education, data = df) That when using summary(lm.all) the output is the same as running multiple univariate regressions (so per each outcome). How do I take into account the correlations between my outcomes?

I just browsed through this wonderful book: . The irony is, I am still not able to understand the motivation for using multivariate (regression) models instead of separate univariate (regression) models. I went through stats.statexchange posts  and  that explain (a) difference between multiple and multivariate regression and (b) interpretation of multivariate regression results, but I am not able to tweak out the use of multivariate statistical models from all the information I get online about them.   My questions are:   Why do we need multivariate regression? What is the advantage of considering outcomes simultaneously rather than individually, in order to draw inferences. When to use multivariate models and when to use multiple univariate models (for multiple outcomes).  Take an example given in the  with three outcomes: locus of control, self-concept, and motivation. With respect to 1. and 2., can we compare the analysis when we do three univariate multiple regression versus one multivariate multiple regression? How to justify one over another? I haven't come across many scholarly papers that utilize multivariate statistical models. Is this because of the multivariate normality assumption, the complexity of model fitting/interpretation or any other specific reason?


I have two heavy bags, so I am looking for good suggestions \ options to go  from the Hotel Westminster (perched between Opera \ Pyramides) to CDG for a 10AM Monday morning international flight.  Update: I should have noted there are two passengers. Tradeoffs to be considered include:   cost  speed  convenience (lines, pickup modality, etc)   Although I have seen at least 3 transportation options, I suspect there may be others and look forward to other good options.

Paris has 3 airports (Orly, Roissy, Beauvais), what are the options to go to or to come from there?  (There is also Vatry (XCR) but there is very few flights and i see the shuttle system is currently off.)


In an answer to this question, For what values of $r$ does $y=e^{rx}$ satisfy $y'' + 5y' - 6y = 0$?, URL (version: 2013-11-13):   $y' = [e^{rx}] (r)$  $y''= r^2e^{rx}$  It says:  If you plug them in, you obtain : $$r^2+5r-6=0$$ Solving this equation you get $r=1$ or $r=-6$. That means that the general solution of the suggested ODE is : $$y(x)=ae^t + be^{-6t}, (a,b) \in \Bbb R^2$$  What do 'general solution' and ODE mean? Where does the last equation come from and what is its significance?

I understand how to find the general solution of a differential equation, for complex roots, simple roots, nonhomogeneous equations etc... but I still don't really know what the general solution is?   As in, what is the purpose of it? What is it used for? thanks...


How to check downloaded file against its hash (SHA-256 Hash, SHA-1 Hash, MD5 Hash) on windows?

Is there a built-in checksum/hash utility on Windows 7?


I was at an English lesson and I said “a live organism”, but the teacher immediately interrupted and said “you should have said “a living organism”” “I didn’t catch that” said I. and a classmate of mine said as the teacher had done. Then I told them that “ a live something and a living something are both correct because they are both adjectives” What is the difference between these ones? I know that there has already been another question, but an answer has not been chosen, I have  also seen some answers which are different from the ones in this website.

Can you think of any situation where the following could be used interchangeably or vice versa?  live  living  Any help would be greatly appreciated