I am currently reading the book "Visual Complex Analysis". It's a great book so far, but already in the beginning the proof of the identity theorem seems dubious. I mean, it's known from high-school algebra, that you're not allowed to divide by z if you set z = 0.  Isn't this proof completely wrong? Some friends I've asked even told me that this theorem is wrong in the reals, so wouldn't a correct proof have to use properties of the complex numbers? Is it even possible to prove this with elementary methods? I've seen proofs that use properties of holomorphic functions but haven't gotten that far in my book yet, so I have no experience with holomorphic functions.

I have troubles understanding a proof in "Visual Complex Analysis". What we want to show is that for two powerseries $c_0 + c_1z + c_2z^2 + ...$  and $d_0 + d_1z + d_2z^2 + ...$, equality in a neighborhood of 0 implies their coefficients must be equal. The proof in the book is the following(translated from german to english):  "Seting  $z=0$ we get $ c_0 = d_0$ so we can cut them out of both equations. Dividing by z and setting $z=0$ it follows that $c_1 = d_1$. Repeating this argument we get that all the coefficients are equal".  Why can we divide by $z$? Where does this proof use that the two powerseries are equal in a neighborhood of 0?


I have a Customer.jsp file on the server to send the content in an Excel file. I have kept the simple text "TestContent" to help me debug this.  <%     response.setContentType("application/vnd.ms-excel");     response.setHeader("Content-Disposition", "attachment;filename=Test.xls"); %>  TestContent   When I download the file on the client side open, Excel(version 2013 or 2016) opens the file, but I get the following message:     The file format and extension of Test.xls don't match. The file could be corrupted or unsafe. Unless you trust its source, don't open it. Do you want to open it anyway?   I have also tried to set the header   application/vnd.openxmlformats-officedocument.spreadsheetml.sheet`    and file format as .xlsx, but it also doesn't help because the warning still appears.    To address the duplicate notice, in the  the author says to not use plain HTML tables with an application/vnd.ms-excel content type. However, because I'm not using any html content, so how would that solution affect my situation (removing the warning)? I have padded all the request headers and content.  Also the target question asks     Is it possible under tomcat to just write a file as if it was a normal Java application [...] ?

I have this application I'm developing in JSP and I wish to export some data from the database in XLS (MS Excel format).  Is it possible under tomcat to just write a file as if it was a normal Java application, and then generate a link to this file? Or do I need to use a specific API for it?   Will I have permission problems when doing this?


I have something like this  Type MyType = Type.GetType(FromSomewhereElse);  var listS = context.GetList<MyType>().ToList();   I would like to get the Type which is MyType in this case and pass it to the Generic Type method GetList  This is the error I am getting:     The type or namespace name 'MyType' could not be found (are you missing a using directive or an assembly reference?)

What's the best way to call a generic method when the type parameter isn't known at compile time, but instead is obtained dynamically at runtime?  Consider the following sample code - inside the Example() method, what's the most concise way to invoke GenericMethod<T>() using the Type stored in the myType variable?  public class Sample {     public void Example(string typeName)     {         Type myType = FindType(typeName);          // What goes here to call GenericMethod<T>()?         GenericMethod<myType>(); // This doesn't work          // What changes to call StaticMethod<T>()?         Sample.StaticMethod<myType>(); // This also doesn't work     }      public void GenericMethod<T>()     {         // ...     }      public static void StaticMethod<T>()     {         //...     } }


At school I learned that a linked list consists of elements with a pointer to the next element in the list, and that a disadvantage with linked lists is that finding the size has linear complexity because you have to go through each element and count. I noticed however that in C++11, std::list.size() has constant complexity. How is this possible?

Recently, I noticed some people mentioning that std::list::size() has a linear complexity. According to  , this is in fact implementation dependent as the standard doesn't say what the complexity has to be. The comment  says:     Actually, it depends on which STL you   are using. Microsoft Visual Studio V6   implements size() as {return (_Size);   } whereas gcc (at least in versions   3.3.2 and 4.1.0) do it as { return std::distance(begin(), end()); } The   first has constant speed, the second   has o(N) speed    So my guess is that for the VC++ crowd size() has constant complexity as Dinkumware probably won't have changed that fact since VC6. Am I right there? What does it look like currently in gcc? If it is really O(n), why did the developers choose to do so?


In Outlook 2016, I created some rules to automatically move emails received in Inbox to self-created folders, according to who the senders are.   Now when Outlook receives a new email and move it to a folder according to some rule, it doesn't notify me. Can it notify me for any incoming email, regardless of whether it is subject to some rule or not and then moved to a folder or stay in Inbox? Now I can only manage to list all the emails in a folder in a single view in time reverse order. Is it possible to list all the emails, regardless in which folders they are stored, in a single view, in reverse time order?   Thanks.

I have rules set up in Outlook 2010 to move a copy of an email from a particular person to a particular subfolder of a folder   i.e. I have folder Team with subfolders, Joe, Mark, Nige  and  Becky. A rule is applied to incoming email that moves a copy of messages from these 4 to their specific folder.   Now what I want is to be able to see all these messages together in the Staff folder (like a specific inbox) too. Is this possible?


How can I prove that the set of all functions from $\mathbb{N} \to \{0, 1\}$ is uncountable?  Edit:  This answer came to mind.  Is it correct?  This answer just came to mind.  By contradiction suppose the set is $\{f_n\}_{n \in \mathbb{N}}$.  Define the function $f: \mathbb{N} \to \{0,1\}$ by $f(n) \ne f_n(n)$.  Then $f \notin\{f_n\}_{n \in \mathbb{N}}$.

Recall that a countable set $S$ implies that there exists a bijection $\mathbb{N}\to S$. Now, I consider (0,1). I want to prove by contradiction that $(0,1)$ is not countable.  First, I assume the contrary that there exists a bijection $f$, and I can find an element in $S$, but not in the range of $f$. But I can't find such element. How can you construct such $f$?


, and I felt foolish after I had some initial difficulty with the first one, so I spent way too much time trying to figure out the next one before .  But all of the rest of them are basically impossible.  For the second one, the satellite information doesn't help at all and       is a really just an obscure chemical where only the shape matters   For the third one, I don't know how anyone could figure it out:      Except for maybe astronomers who are really good at knowing the shapes of all the constellations   The fourth one might be reasonable, but Wikipedia didn't have information about any of the ones I tried  The Fifth and sixth answers I'm quite familiar with, and I can't find any way to figure out how to figure them out.  Did google expect us to brute force the solutions somehow?

Google released a new online game at    And it appears as if the first step is determining the cluster name, but I can't figure out how to determine the cluster name.  I've tried typing in random strings found around the console, and pieces of various satellite properties, but I'm stuck.  I would prefer not just knowing the answer, but how I'm supposed to figure it out. Is there a help option I'm not reading? Is this supposed to be some deep hacking of the javascript (it appears to be sending data to a server to be validated, so I don't think source loading will help.)


For example, if I have something like blah blah blah blah $\frac{1}{1+2x-x^2} + 6$ blah blah blah  The equation will look compressed compared to \begin{equation} \frac{1}{1+2x-x^2} + 6 \end{equation}  I want my equation to not be compressed like the second code but be in line with the text like the first code. How do I do this?

I'm very familiar with how symbols display differently in inline mode (with $ ... $) vs. how display math shows them (with \[ ... \] or $$ ... $$).  Two examples would be with limits  $\lim_{n\rightarrow \infty}f(x)$   vs.  \[ \lim_{n\rightarrow \infty}f(x) \]   and with sums  $\sum_{n=1}^{x} n^2$   vs.  \[ \sum_{n=1}^{x} n^2 \]   My Question is:     How do you display these things in inline mode (with all the nice inline formatting) as if they were in display mode ?   The inverse -- how to display things in display mode as if they were in inline mode -- is also of interest.


1) Prove that $(1+x)^{n} \geq 1 + nx$ for every $n \in \mathbb{N}$ and $x \in (-1, \infty)$  Base case: Usually for the base case I just take $n = 1$ but since there's another variable $x$, I wasn't sure which value to use for $x$, so I just set $x = -1$. Not sure if this is correct...  $(1 - 1)^{1} \geq 1 - 1$ which stands, so I proceed with the proof.  $n \rightarrow n + 1$: Assume $(1+x)^{n} \geq 1 + nx$ for every $n \in \mathbb{N}$ and $x \in (-1, \infty)$. I want to show that $(1 + x)^{n + 1} \geq 1 + (n + 1) x$ for every $n \in \mathbb{N}$ and $x \in (-1, \infty)$  $(1 + x)^{n} \cdot (1 + x) \geq (1 + nx) (1 + x)$ by the induction hypothesis  $\Rightarrow (1 + x)^{n + 1} \geq 1 + x + nx + nx^{2} \geq 1 + nx + x$  $ \square$  2) Prove that $\sum_{i = 1}^{n} i(i + 1) = n(n + 1)\frac{(n + 2)}{3}$ for all $n \in \mathbb{N}$  Base case: I get thrown off by $i$ (just like how I got throw off by $x$ in the previous problem), but I just set $i = 1$ and the base case stands:  $1( 1 + 1) = 1 \cdot 2 \cdot 1 \Rightarrow 2 = 2$  So I proceed with the proof.  $n \rightarrow n + 1$: Assume that $\sum_{i = 1}^{n} i(i + 1) = n(n + 1)\frac{(n + 2)}{3}$ for all $n \in \mathbb{N}$, want to show that...  $i(i + 1) = (n + 1)(n + 2) \frac{(n + 3)}{3}$ for all $n \in \mathbb{N}$  Is this correct? If so, wouldn't that imply $(n + 1)(n + 2) \frac{(n + 3)}{3} = n(n + 1)\frac{(n + 2)}{3}$? And that doesn't really make sense to me.

Use mathematical induction to prove this. Here is my answer but I stuck at certain point.   Base Case:           n=1  $$(1+x)^1 \ge 1+x $$ True ,   Induction Case:           n=k assume    $$(1+x)^k \ge 1+kx $$           n=k+1           $$ (1+x)^k+1 \ge 1+(k+1)x $$           $$(1+x)^k *(1+x) \ge 1+ kx+ x $$        Stuck!!!


I am stuck with downloading project code for an android application on code.google.com.   My college have proxy settings issues while trying to download via terminal using Git.  Could somebody provide a link or way to do so.

Note: while the use-case described is about using submodules within a project, the same applies to a normal git clone of a repository over HTTP.  I have a project under Git control.  I'd like to add a submodule:  git submodule add http://github.com/jscruggs/metric_fu.git vendor/plugins/metric_fu   But I get  ... got 1b0313f016d98e556396c91d08127c59722762d0 got 4c42d44a9221209293e5f3eb7e662a1571b09421 got b0d6414e3ca5c2fb4b95b7712c7edbf7d2becac7 error: Unable to find abc07fcf79aebed56497e3894c6c3c06046f913a under http://github.com/jscruggs/metri... Cannot obtain needed commit abc07fcf79aebed56497e3894c6c3c06046f913a while processing commit ee576543b3a0820cc966cc10cc41e6ffb3415658. fatal: Fetch failed. Clone of 'http://github.com/jscruggs/metric_fu.git' into submodule path 'vendor/plugins/metric_fu'   I have my HTTP_PROXY set up:  c:\project> echo %HTTP_PROXY% http://proxy.mycompany:80   I even have a global Git setting for the http proxy:  c:\project> git config --get http.proxy http://proxy.mycompany:80   Has anybody gotten HTTP fetches to consistently work through a proxy?  What's really strange is that a few project on GitHub work fine ( for example), but others consistently fail ( for example).


I have a question about a note given in a linear algebra textbook. It is just given as a remark, with no proof or explanation so I want to make sure I understand it correctly.  First, it gives the definition of the eigenspace of A to be, The set, $$E_{\lambda}=\{{v \in \mathbb R^n : Av= \lambda v}\}$$  and it then notes, from this we can see that because $E_{0}=N(A)$, this $\rightarrow$ a matrix is singular if and only if $\lambda=0$  is an eigenvalue.  But I am still a little confused. If I am recalling correctly, a  transformation is singular if there exists a $v  \neq 0$ for which $T(v)=0$  I guess in this case it is in regard to if  a matrix is invertible or not? I think I may be getting confused between the two differences ( if there is one) and the differences between talking about just A and a transformation in general.  Anyone have any advice /explanations for this?  Thank you!

If the $\det(A)=0$ why does the matrix $A$ have an eigenvector? Explain why there is a basis $B$ in $R^n$ so that the matrix $[A]_B$ has the zero vector as its first column   I know that if the $\det(A)=0$ of a matrix is zero then it is singular and thus not invertible. That in turn means that it doesn't have one solution. Why does that mean that it has an eigenvector?  As for the second I have no idea.


I have the same problem with this topic   My problem is that what should I do if I want a result:  1 | A, B 2 | A

I'm trying to migrate a MySQL-based app over to Microsoft SQL Server 2005 (not by choice, but that's life).  In the original app, we used almost entirely ANSI-SQL compliant statements, with one significant exception -- we used MySQL's group_concat function fairly frequently.  group_concat, by the way, does this: given a table of, say, employee names and projects...  SELECT empName, projID FROM project_members;   returns:  ANDY   |  A100 ANDY   |  B391 ANDY   |  X010 TOM    |  A100 TOM    |  A510   ... and here's what you get with group_concat:  SELECT      empName, group_concat(projID SEPARATOR ' / ')  FROM      project_members  GROUP BY      empName;   returns:  ANDY   |  A100 / B391 / X010 TOM    |  A100 / A510   So what I'd like to know is: Is it possible to write, say, a user-defined function in SQL Server which emulates the functionality of group_concat?   I have almost no experience using UDFs, stored procedures, or anything like that, just straight-up SQL, so please err on the side of too much explanation :)


I am trying to implement my own BigInteger class with overloaded operators. So I have bool operator<(const BigInteger& left, const BigInteger& right) {   // some code }  which works OK, and now I try to overload operator< also as following: template <typename T> bool operator<(const BigInteger& left, const T& right) {   BigInteger big_right(right);   return (left < big_right); }  But in main.cpp following code numeric::types::BigInteger a{17}; std::cout << std::boolalpha; std::cout << (a < 16) << std::endl;  cannot compile, error undefined reference to 'bool numeric::types::operator< <int>(numeric::types::BigInteger const&, int const&)' P.S. BigInteger is in namespace numeric::types {} BigInteger of course has int constructor: BigInteger::BigInteger(int int_number) {   // some code }  Is it possible to somehow make this work? P.P.S. This is not anyhow connected with , because BigInteger is just class BigInteger, not a template <typename T> class BigInteger So in code numeric::types::BigInteger a{10}; std::cout << (a < 2) << std::endl; std::cout << (a < 2LL) << std::endl;  both of cout's should work correctly

Quote from :     The only portable way of using templates at the moment is to implement them in header files by using inline functions.   Why is this?  (Clarification: header files are not the only portable solution. But they are the most convenient portable solution.)


What was the name of the person who phoned?      I'm wondering what does this question really mean? Does it mean:         What is the name of the person who phoned?      but why was instead of is?  or means         What was the name of the person who had phoned?

I know the past tense carries the past tense in every dependent clause, but referring specifically to places or to things that are eternal, like the Earth, seems a bit weird and therefore we sometimes (I believe incorrectly) say     He didn't know that New Jersey was actually on the East Coast.   Because it still is. Or     He thought the Earth was round.   So is it square now?  Logically speaking, would you consider the use of past tense here a bit confusing in a day-to-day speech in these examples? Would you instinctively opt for using the present tense?


From SEO perspective, which language code format in the URL is better and more correct? www.example.com/en-US www.example.com/en_US    Is the second format valid for the attribute hreflang in <link rel="alternate".....>? According to , the first format en-US is always described.   I have already done my website with the second format en_US. Is it worth to move to the first format if it is a better one.  [UPDATE]  Rather than trying to find an answer to choose underscores or dashes in URL, I would like to know about the correct language code usage in URL. For example, as I already used the en_US format, what is the correct usage?  <link rel="alternate" href="http://www.example.com/en_US" hreflang="en_US" />  <link rel="alternate" href="http://www.example.com/en_US" hreflang="en-US" />

Which is better for search engines?   example.com/my_cool_page.html example.com/my-cool-page.html  example.com/my+cool+page.html


I want to find an algorithm that given a set A to find all groups of subsets that satisfy the following condition:     x ∪ y ∪ .... z = A, where x, y, ... z ∈ Group   and      ∀ x,y ∈ Group: x ⊆ A, y ⊆ A, x ∩ y = ∅ = {}   and      ∀ x ∈ Group: x != ∅   Note: I hope to define it well, I'm not good with math symbols  I made the following approach to search groups of two subsets only:  from itertools import product, combinations  def my_combos(A):   subsets = []   for i in xrange(1, len(A)):     subsets.append(list(combinations(A,i)))   combos = []   for i in xrange(1, 1+len(subsets)/2):     combos.extend(list(product(subsets[i-1], subsets[-i])))   if not len(A) % 2:     combos.extend(list(combinations(subsets[len(A)/2-1], 2)))   return [combo for combo in combos if not set(combo[0]) & set(combo[1])]  my_combos({1,2,3,4})   I get the following output, these are all groups composed of two subsets  [   ((1,), (2, 3, 4)),    ((2,), (1, 3, 4)),    ((3,), (1, 2, 4)),    ((4,), (1, 2, 3)),    ((1, 2), (3, 4)),    ((1, 3), (2, 4)),    ((1, 4), (2, 3)) ]   ..... but, groups composed of one, three, four subsets ....   Question:  how may i find a general solution?   for example the following expected output:  my_combos({1,2,3,4})  [   ((1,2,3,4)),   ((1,2,3),(4,)),   ((1,2,4),(3,)),   ((1,3,4),(2,)),   ((2,3,4),(1,)),   ((1,2),(3,4)),   ((1,3),(2,4)),   ((1,4),(2,3)),   ((1,2),(3,),(4,)),   ((1,3),(2,),(4,)),   ((1,4),(2,),(3,)),   ((1,),(2,),(3,4)),   ((1,),(3,),(2,4)),   ((1,),(4,),(2,3)),   ((1,),(4,),(2,),(3,)) ]

I am writing a program in Python, and I realized that a problem I need to solve requires me, given a set S with n elements (|S|=n), to test a function on all possible subsets of a certain order m (i.e. with m number of elements). To use the answer to produce a partial solution, and then try again with the next order m=m+1, until m=n.  I am on my way to write a solution of the form:  def findsubsets(S, m):     subsets = set([])     ...     return subsets   But knowing Python I expected a solution to be already there.  What is the best way to accomplish this?


Given a ring $A$, By the chain of prime ideals of $A$, we mean a sequence of prime ideals of $A$ such that $P_0 \subsetneq P_1 \dots \subsetneq P_{n-1}\subsetneq P_n$. Further this chain has a length $n$.  Define the dimension of a ring $A$ by $\operatorname{Dim}(A)$ to the supremum the lengths of all chains of prime ideals of $A$.     Show that if $\operatorname{Dim}(A)=0$ then every prime ideal is maximal.   Attempt: Suppose that there exists a prime ideal $X$ which is not maximal, then there exists an ideal $Y\subsetneq A$ properly containing $X$. Now my aim is to show that there exist a sequence of prime ideals $P_0 \subsetneq P_1 \dots \subsetneq P_{n-1}\subsetneq P_n$ with $n \geq 1$. I am getting $Y$ as an ideal. I am not getting any prime ideal after that. How should I proceed from here?  Also I cannot use $0=\{0\}$ since $0$ is not a prime ideal.

Let $R$ be a ring, If we assume '$R$'s all prime ideals are maximal',then we can say $R$'s krull dimension is exactly $0$. This is easy because there are two different prime ideal $p$ and $q$ which satisfies $p⊂q⊂R$, and this contradicts the fact that $p$ is maximal.  But is the converse true?  my attempt: If there are prime ideal $p$ which is not maximal, then there are another ideal $q$ which satisfies $p⊂q⊂R$. If I can deduce $q$ is prime ideal, the proof are done.But I cannot show $q$ is a prime ideal.  Any help would be appreciated, thank you.


Here, by inertia, I mean the tendency of an object to retain its state of motion and resist change. Another way of defining inertia is how much force is needed to create a certain amount of acceleration. And so quantitatively, this would be equal to F/a. Then the specific quantity that would determine the amount of inertia I suppose would be $\gamma^3 m$, which can also be called relativistic mass, but I have been advised not to use that term as it is apparently becoming obsolete. However that is a minor issue, and the main point to my question is that this would imply that an object can simultaneously have multiple values for $\gamma^3 m$ and therefore inertia depending on the frame. How can that be? This would imply that there can be multiple possible accelerations for a given force because there will be different values for $\gamma^3 m$ depending on the reference frame. So which $\gamma^3 m$ in which reference frame ultimately determines how much acceleration a certain force will produce? If it depends on the frame of the object that the force is acting on, then it would mean it is the invariant mass of the object that determines the inertia. In that case inertia would not increase with velocity and this would also imply that a finite amount of force and energy can make an object with mass move at speeds equal to or higher than the speed of light. Doesn't this create conflicting realities?

Would inertia grow differently if we switch the reference frame?  LHC accelerator makes protons x7000 heavier at record speeds and I just wonder if we could change the reference frame (keeping velocity), would its mass be different? (eg. in vacuum, far from any gravitational field). If velocity is relative, we can say that protons are in rest and any other frames are moving at that velocity in opposite direction...


In Star Trek: Beyond I noticed that Kirk ejects directly from the bridge when the Enterprise is going to crash.   Does he have the only escape pod that ejects from the bridge? Is is so he can give final orders on the bridge before ejecting?   Surely there is not enough room on the bridge for all the crew. Do other key members of the crew have their escape pods at their respective stations?   I would expect to find Bones' pod in the sickbay.   Do the enlisted crew have their pods down below or perhaps at a muster area?

In Star Trek Beyond, Captain Kirk orders the crew to abandon ship. I assume they do so in normal ole escape pods. But, then, Kirk instructs Sulu to get into his Kelvin pod. Since he called it by name, I have to assume it is special.     I found on :      The Kelvin pod was a type of escape pod that were attached to the USS Enterprise in 2263. Kelvin pods were stowed beneath the bridge of the Constitution-class ship, allowing quick egress for the command crew in the event of a catastrophic event.   My question is, how are they different and where in the movie (or externally) is this confirmed.


I need to write a Java Comparator class that compares Strings, however with one twist.  If the two strings it is comparing are the same at the beginning and end of the string are the same, and the middle part that differs is an integer, then compare based on the numeric values of those integers.  For example, I want the following strings to end up in order they're shown:   aaa bbb 3 ccc bbb 12 ccc ccc 11 ddd eee 3 ddd jpeg2000 eee eee 12 ddd jpeg2000 eee   As you can see, there might be other integers in the string, so I can't just use regular expressions to break out any integer.  I'm thinking of just walking the strings from the beginning until I find a bit that doesn't match, then walking in from the end until I find a bit that doesn't match, and then comparing the bit in the middle to the regular expression "[0-9]+", and if it compares, then doing a numeric comparison, otherwise doing a lexical comparison.  Is there a better way?  Update I don't think I can guarantee that the other numbers in the string, the ones that may match, don't have spaces around them, or that the ones that differ do have spaces.


A student is applying to PhD program in Computer Sciences at Harvard and MIT. He estimates that he has two to three chances of being accepted at Harvard and two out of five chances at MIT. He further estimates the probability that he will be accepted by both with probability of one to five. What is the probability that he is accepted by MIT if he is accepted by Harvard?   I think that the answer will be P(M|H)=(1/5)/(2/3)=0.3, but I'm confused about the condition of the problem. Why do we need to know that P(M)=2/5 if we don't use it? Or should I prove that the events are not independent before using the formula P(M|H)? So it would be P(M and H)=P(H)·P(M|H)=1/5=0.2  I'd really appreciate a piece of adivce. Thank you in advance!

A student is applying to a PhD program in Computer Sciences at Harvard and MIT. He estimates that he has two out of three chances of being accepted at Harvard and two out of five chances at MIT. He further estimates the probability that he will be accepted by both has probability of one to five. What is the probability that he is accepted by MIT if he is accepted by Harvard? Is the event "accepted by MIT" independent of the event "accepted by Harvard".  I don't understand if these are odds or probabilities


How do i get rid of the grease pencil marks in blender? I put a couple marks on my mesh by mistake and i want to get rid of em all. I already tried using erase and it doesn't work.

I have plenty of grease pencil sketches in my blend file. Is it possible to remove all of them very fast?


I am relatively new to Ubuntu, I noticed that in answers on this site, when people suggest editing system files, the command they give is always sudo nano or sudo vi. Because I dislike using terminal based text editors, I usually use   sudo -H gedit   instead, and so far it worked perfectly fine.  Can there ever be any problem with using gedit to edit system files or is choice of text editor is purely up to the person's preference? Is there anything that I should keep in mind (like encoding) when editing these files?

I've read  and am interested in this line:     You should never use normal sudo to start graphical applications as Root.   Why? What is the difference? Please provide a simple explanation, as I'm just a normal desktop user.


Let the sequence $(x_n)$ with $x_1=1$, $x_{n+1}=x_n+\sqrt{x_n^2+1}$, for all $n\ge 1$. Compute $$\lim_{n\to \infty}\frac{2^n}{x_n}.$$ My idea: It is easy to check that the sequence $(x_n)$ satisfies $x_n>0, \forall n\ge 1$, then $x_{n+1}>2x_n$. Thus $\frac{2^n}{x_n}>\frac{2^{n+1}}{x_{n+1}}, \forall n\ge 1$, so the sequence $\left(\frac{2^n}{x_n}\right)$ is decreasing. Since it is obviously bounded by $0$, by Weierstrass's Theorem it follows that the sequence $\left(\frac{2^n}{x_n}\right)$ is convergent. However, I couldn't find the limit's value. Please help me! Thank you!

Be $(x_n)_n\ge 1 $  such that $x_1=1$ and $x_{n+1}=x_n+\sqrt{x_n^2+1}$ for every $n\ge 1$. Prove that the sequence $y_n=(2^n/x_n)_n \ge 1$ is convergent and find it s limit.  Being positive and decreasing, $y_n$ is clearly convergent. But finding it's limit really put me intro trouble. Any help?  Thank you!


(Note: I have a specific question in mind but I'm asking this one in the general case as it may apply to others. I've added an explanation for the specific case at the end.)  It can happen that a question is on-topic on more than one Stack Exchange website. Unless I'm mistaken, asking it on either of them is acceptable.  If it is posted on one of the websites but has not received an answer that solves the problem in a timely fashion, and there is reason to think that it can receive better answers on the other website, should it be re-asked on that one?  Migration may not be an option due to the question being .  The question that prompted this one is . I believe it is equally on-topic in Arqade and Superuser, but that the people most qualified to answer it may be on Superuser, as it is essentially about SMB/samba.

I've seen a question on a site I don't have an account on. The question was very interesting and it's also on-topic on this other site, where I am an active user on.  The question is on-topic on both sites.  Is it OK for me to post the same question (possibly with linking to the original) on the site I'm active on?


Let $A$ $\in M_3(\mathbb R)$ which is not a diagonal matrix. Pick out the cases when $A$ is diagonalizable over $\mathbb R$:  a. when $A^2 = A$;  b. when $(A - 3I)^2 = 0$;  c. when $A^2 + I = 0$.  I could eliminate c. by using the equation $\lambda^2+1$ and showing if a matrix has to satisfy this then it has to be diagonal.  I am also in doubt whether all the eigen values of $A$ satisfy this or not.

Let $A$ belongs to $M_3(\mathbb R)$ which is not a diagonal matrix. Pick out the cases  when $A$ is diagonalizable over $\mathbb R$:  a. when $A^2 = A$; b. when $(A - 3I)^2 = 0$; c. when $A^2 + I = 0$  (a) is certainly true as eigen values are distinct. (c) is certainly not true as eigen values are imaginary not real. but i am not sure about (b). can anybody help? thanks.


I'm trying to solve the following exercise from the book A Textbook of Graph Theory by R. Balakrishnan and K. Ranganathan     Show that for a simple bipartite graph, $m\leq \frac{n^2}{4}$   $m$ is the size of the graph.  $n$ number of vertices.  I was considering the following cases:  Let $X$ and $Y$ be a partition of the set of vertices of $V(G)$ and I tried to verify some cases accordingly to the cardinality of the each set. If $|V(G)|=n$ and $|X|=|Y|=\frac{n}{2}$ it is easy to see, but I got stuck trying to show the case when the cardinalities are $|X|<|Y|$  Any help will be greatly appreciated!  Thanks!

Prove that for a bipartite graph $G$ on $n$ vertices the number of edges in $G$ is at most $\frac{n^2}{4}$.     I used induction on $n$.    Induction hypothesis: Suppose for a bipartite graph with less than $n$ vertices the result holds true.    Now take a bipartite graph on $n$ vertices.Let $x,y$ be two vertices in $G$ where an edge exist between $x$ and $y$. Now remove these two vertices from $G$ and consider this graph $G'$. $G'$ has at most ${(n-2)^2}\over4$. Add these two vertices back.  Then the number of edges $G$ can have is at most    $$|E(G')|+d(x)+d(y)-1$$   My question is in my proof I took $d(x) + d(y) \le n$, where $d(x)$ denotes the degree of vertex $x$.  Can I consider $d(x)+d(y) \leq n$? I thought the maximum number of edges is obtained at the situation $K_{\frac n 2,\frac n 2}$


In Harry Potter and the Order of the Phoenix, Harry has a vision of himself attacking Mr. Weasley. Harry explains to Dumbledore what happened and the Dumbledore does this:  Dumbledore now swooped down upon one of the fragile silver instruments whose function Harry had never known, carried it over to his desk, sat down facing them again and tapped it gently with the tip of his wand. The instrument tinkled into life at once with rhythmic clinking noises. Tiny puffs of pale green smoke issued from the minuscule silver tube at the top. Dumbledore watched the smoke closely, his brow furrowed. After a few seconds, the tiny puffs became a steady stream of smoke that thickened and coiled in the air . . . a serpent's head grew out of the end of it, opening its mouth wide. Harry wondered whether the instrument was confirming his story: he looked eagerly at Dumbledore for a sign that he was right, but Dumbledore did not look up. 'Naturally, naturally,' murmured Dumbledore apparently to himself, still observing the stream of smoke without the slightest sign of surprise. 'But in essence divided?' Harry could make neither head nor tail of this question. The smoke serpent, however, split itself instantly into two snakes, both coiling and undulating in the dark air. With a look of grim satisfaction, Dumbledore gave the instrument another gentle tap with his wand: the clinking noise slowed and died and the smoke serpents grew faint, became a formless haze and vanished.  The snake is obviously related to Harry's dream. Does it read his mind? Why does the snake split?

In Order of the Phoenix, Dumbledore uses a small silver instrument that puffs pale green smoke and shows him a snake, to which he then says, "Naturally, naturally, but in essence divided?" It then turns into two snakes. What exactly is the significance of this? And what is the function of the instrument?  This happens right after Harry has a vision of Mr. Weasley being attacked by the snake in the Ministry of Magic.


I'm attempting to make boot Ubuntu as a kiosk and I'm very very close. I've got the splash screens setup for grub and a new theme for plymouth. They work and look great. I do have a couple issues remaining.   The main one appears to be a message from fsck during boot: /dev/sda2: clean, xxx/xxxx files, xxxx/xxxxx blocks This removes the splash screen and shows text instead. I have tried adding GRUB_CMDLINE_LINUX=console=tty11 expecting it to print output to a different console than the splash, but instead it just disabled the splash entirely.  The other issue isn't all that important. There is a blank screen after the rub splash, and the kernel boot splash. What is this, and is there a way to fill it ?  Edit:  I replaced quiet with loglevel=2 and instead of the single /dev/sda2: clean statement, I get the system boot up text instead. So it gets worse.  However I did add fsck.mode=skip to GRUB_CMDLINE_LINUX_DEFAULT and that got rid of the message. Not sure I'm comfortable with skipping the fsck though. I will keep investigating.

What I want to achieve:  I want to customize my complete boot of my Ubuntu 16.04 LTS installation  to show the same wallpaper which is actually on my desktop.  What I achieved till now:   added the wallpaper to the grub menu by adding the following lines to /etc/deault/grub and doing an update-grub afterwards.  export GRUB_MENU_PICTURE="/boot/grub/wallpaper.png" export GRUB_COLOR_NORMAL="white/black" export GRUB_COLOR_HIGHLIGHT="black/white"  added the wallpaper to the splash-screen and login screen   Problem:  When I boot up the picture is showing while in grub, but then I rarely see the splash screen, instead I get an almost blank screen showing the file-system check like following:  /dev/sda1: clean, 201776/60878736 files, 4991277/243040256 blocks   This prevents me from having the boot experience I want to achieve since after that the splash-screen just shortly popping up after that message.  Question:  How can I remove this message from showing up so I get a seamless booting with my beloved wallpaper, without switching the file-system check completely off (if possible)?


In Star Trek: Voyager, there is a big deal made about them warping far beyond contact with any Federation bases, beause they're all the way out in "the Delta Quadrant".    To me, this indicates that there is a finite area of space that has been explored in the Star Trek universe up to this point.    So, including for the sake of this question the Delta Quadrant that they were lost in, and all of explored Space up to that point in the series, how much of Space is included in the Federation-explored region of the Star Trek Universe?    Actual units of measurement would be ideal, but are not required if a general idea would better describe the size of the known universe.

All throughout Star Trek one hears of exploration of various quadrants. I assume these are of the Milky Way galaxy. Does anyone know how the travels of the Enterprise relate to our universe in physical space? Was the entire series limited to our galaxy, or did the crew ever visit other galaxies?  In short, what area of the universe was Star Trek exploring?


Consider following MWE:  \documentclass[varwidth]{standalone}  \usepackage{biblatex} % version 3.3 with biber 2.4 (TexLive 2015) \begin{filecontents}{\jobname.bib} @article{example,   author  = {AUTHOR A, AUTHOR B},   journal = {NAME OF JOURNAL},   title   =  {NAME OF PAPER},   year    = {2016},   volume  = {12}, } \end{filecontents} \addbibresource{\jobname.bib}  \begin{document}  \begin{itemize}   \item \citefield{example}{author}   \item \citefield{example}{journal}   \item \citefield{example}{title}   \item \citefield{example}{year}   \item \citefield{example}{volume} \end{itemize}  \fullcite{example} \end{document}     As you can see author and journal are not given. What is the problem or is there a bug in this biblatex version?

I want to automate personal reading notes generation, I'd like to be able to automatically extract a field's content from a BibTeX entry (other than year or author).  E.g. given a BibTeX entry  @article{einstein05,    author={Albert Einstein},    title={Zur Elektrodynamik bewegter K{\"o}rper},    abstract={Interesting article, which claims that time is relative.},    journal={Annalen der Physik und Chemie},    volume={17},    year={1905},    pages={891--921} }   I want to have a macro in my TeX file (e.g. \citeabstract) that will return the string Interesting article, which claims that time is relative. (the same for DOI, etc.)  I've found the \printfield command that might help me, but I'm not smart enough to know how to use it.  I don't know if it has any influence on the answer, but I'm using BibLaTeX+BibTeX.


I'm a new user of ubuntu and have messed up my system because of lack of information.   Few days back i tried to install WINE WINDOWS PROGRAM LOADER v1.8 on my laptop but during the download my pc got shut down and after that any command releated to wine gives me an error.   Now all i want to do is to completely uninstall it and everthing releated to wine.  I'm using ubuntu 16.04 LTS

How can I remove the wine folder and all the applications in that folder?  I've tried via synaptic but it keeps showing up in the application menu.


We are Filipino Citizens moving to Canada via Jetstar and Air Canada. Our flight itinerary brings us to Osaka for a 5 hr layover before our next flight. We'd like to know if we need to have a VISA for that short amount of stay?

I will be transferring between two international flights at Tokyo Narita airport. I'm scheduled to depart the same day I arrive. I am planning to stay within the airport during the layover. Does anyone know if I will require a transit visa at Narita?


I had the problem when I want to replace attribute img.  In class="HotProject_item HotProject_item_preview isotope-item" content class ="content-asset" have  <img src="/Uploads/images/0110/112/image012.jpg" .    I want to change img src with new image. Can you help me?

 Title ABC

    Decription :)    &nbsp;

    Subtitle    &nbsp;

My DOM looks like this:

   When someone clicks on an image, I want the image src to change to  where x represents the image number 1 or 2.  Is this possible or do I have to use CSS to change the images?


How can I make the integral symbol bigger independent of the rest of equation? The symbol appears with the same size of a delimiter.

Is there a possibility to draw large integral signs?  I have found the package  but I have the feeling it is not very professional...  Any better idea?


When I start a merge in my vagrant botstrap I get a merge conflict:  ==> git merge --no-ff testing/other ==> gc-gw0: Auto-merging manifests/fastd.pp ==> gc-gw0: CONFLICT (content): Merge conflict in manifests/fastd.pp ==> gc-gw0: Automatic merge failed; fix conflicts and then commit the result.   This will stop the bootstrap from functioning although the conflict is really tiny.  How can I automatically take the version of the "other" branch for that file in my script?

When merging topic branch "B" into "A" using git merge, I get some conflicts. I know all the conflicts can be solved using the version in "B".  I am aware of git merge -s ours. But what I want is something like git merge -s theirs.   Why doesn't it exist? How can I achieve the same result after the conflicting merge with existing git commands? (git checkout every unmerged file from B)  UPDATE: The "solution" of just discarding anything from branch A (the merge commit point to B version of the tree) is not what I am looking for.


Can anybody give me some link which proves that winding number is an integer in complex analysis. In most of the links I found they approached in assuming that $$s \mapsto \int_{0}^{s} \frac {\gamma'(t)} {\gamma (t)-a}\ dt$$ is continuous on $[0,1]$ and differentiable on $[0,1]$ except possibly at junction points where $\gamma$ is closed contour with parametric interval $[0,1]$ and $a \notin \{\gamma \}$. I don't understand this thing clearly. So I want a proof which has some clear discussion. Please help me by giving it if there is any.  Thank you in advance.

How could I explain mathematically, that the winding number of a closed curve $\gamma$  around $a$ ($a \notin \gamma$) gives always an integer value. $$ W(\gamma,a)=\frac{1}{2\pi i} \int_{\gamma} \frac{dw}{w-a} $$  where $W(\gamma,a)\in \mathbb{Z}$


This is my data stored as Exist_eutran_freqs.csv:  120,1775 2984,1800 1942,2850 65,150 206,3050 8,1825 45,125   when I want to print them by below gawk command and switch the col1 and col2, I'm getting below output!  Command:  gawk -F'[,]' '{print $2,$1}'  Exist_eutran_freqs.csv   Output:   120  2984  1942  65  206  825  45   what is the solution for this?

When I open the file in Vim, I see strange ^M characters.  Unfortunately, the world's favorite search engine does not do well with special characters in queries, so I'm asking here:   What is this ^M character? How could it have got there? How do I get rid of it?


Some author's name contains special characters like "ł" in Szałowski. The latex code for "ł" is \l.  But if I write the name in bib file as Sza\l owski, the the name contained in the output pdf's reference will be "Szał owski". That is to say, there will be a space in the name.  But if I write Sza\l owski in the main text of latex file, then the name will be ok without space.   So why there will be a space? How to deal special character in bib file?  and a related question: In the main text of LaTeX file, no matter how many space after \l, the output is the same. That is to say, the output of Sza\l owski is the same as that of Sza\l    owski, both output "Szałowski". Then what should I do if I want "Szał owski" in the main text.

How to write in bibliography (package natbib) letter "a" with two dots above? Specially, I mean the word Birkhäuser.  Is there a general rule or way how to write such umlauts or other accented letters in bibliographies?


I am trying to run click event on nested appended elements.           $(document).ready(function () {         var year;         var month;         var day;           $(".table-list").one("click", function (e) {             year = $(this).data("year")             var this_li = $(this)             $.get( "get_months/"+year, function( data ) {               $.each(data, function (key, val) {                   $(this_li).append('

'+val["_id"]+'-'+year+'

')               });             });         });          $(".table-list").delegate(".month-list", "click", function(){             if($(this).data("clicked"))             {                 return false;             }             month = $(this).data("month")             var this_li = $(this)             $.get( "get_days/"+year+"/"+month, function( data ) {              $.each(data, function (key, val) {                   $(this_li).append('

'+val["_id"]+'-'+month+'-'+year+'

')               });              });             $(this).data("clicked", true);           });          $(document).on("click", ".source_list" , function() {         alert("bla")          });      });      But click event on "source_list" not working. How can I access this element with jquery? I also tried delegate but it doesn't work too.

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.


I am really struggling with my References / Bibliography page. I will unfortunately be unable to give much of my code, as the contents of the document are unpublished. The template I was given to use for my code included a refs.txt file that had, \begin{thebibliography}{} \bibitem{}  \end{thebibliography}  Unfortunately, I used the APA citation style when manually citing in my document, so I do not want the number in the brackets ( [1] ) before my citation. I have a main.txt file that then includes my other text files, \include{ch1}        \include{ch2} \include{ch3}        \include{refs}  I believe it is due to this reason that the \usepackage{natbib} package continues to give me an error. Additionally, I have attempted to forgo the thebibliography aspect of my code and attempt to write a .bib file, but when adding it to my main.txt file, under my \include statements (while removing the \include{refs}, as either \printbibliography or \bibliography{example} it does not include my reference page at all. Is there anyway to fix this, or do something completely different, or will I have to redo all of my citations? Edit: I believe I have figured it out on my own.

As you can see in  article on Wikipedia, there is a distinction made between notes, citations and references. I would like to have a section called citations at the end of my document which I can refer to like this[2]  [2] Lasker (1934), p. 73  which is to be found in my references under "Lasker, Emanuel (1934). Lasker's Chess Primer. London: Billings (1988 reprint). ISBN 0-7134-6241-8". Ideally, I would like this citation to contain a hyperlink to this reference (although this is not done in the document). Any good way to do this or something similar?


a few days ago my Apache server randomly started hogging the CPU during which time the site becomes sluggish and unresponsive.   Here is what mod_status shows during an incident:   Nearly all connections are in the waiting state A few connections are in the Keep-Alive state. All of them have Req column values (Milliseconds required to process most recent request) between 15 and 40 seconds, which is 10-20x longer than usual During this time, running top command shows 100% usage of all 4 CPUs, with 5-7 Apache child processes on top, taking 10-40% percent CPU each   Each incident lasts 15-30 minutes and then the situation returns to normal for a while, until another incident occurs.   Server configuration and stats:   Digital Ocean droplet with 4 CPU's, 8 GB RAM LAMP stack running a Wordpress site, about 40K hits per day (XMLRPC protected, wp-login protected) MySQL performance appears normal (slow query logging on, nothing unusual)   Any advice on debugging this would be appreciated as I don't even know where to start.     Server Version: Apache/2.4.7 (Ubuntu) PHP/5.5.9-1ubuntu4.11 Server MPM: prefork Server Built: Jul 24 2015 17:25:11 Current Time: Sunday, 02-Oct-2016 08:41:09 EDT Restart Time: Sunday, 02-Oct-2016 07:55:53 EDT Parent Server Config. Generation: 1 Parent Server MPM Generation: 0 Server uptime: 45 minutes 15 seconds Server load: 105.26 38.36 22.87 Total accesses: 32705 - Total Traffic: 367.2 MB CPU Usage: u455.08 s51.66 cu0 cs0 - 18.7% CPU load 12 requests/sec - 138.5 kB/second - 11.5 kB/request 144 requests currently being processed, 39 idle workers _WWWWWWWWW_WKWWWWW__WWWW._WW.WWWW___W.WWWW__WWW_W_WWWW_WW.W_WWWW _W.WCWW_WW.WKWWWWWWWWW_WWWKW.W_K_.KW__K.W._WWWWW__WWWWWWWWW._WKW WWWK.WW_WW__WWWWWWWW__WWW_WWWW_WWWWWW_._WWWKK___WWW_WWWWWWWWWWWW _.W..WW. Scoreboard Key: "_" Waiting for Connection, "S" Starting up, "R" Reading Request, "W" Sending Reply, "K" Keepalive (read), "D" DNS Lookup, "C" Closing connection, "L" Logging, "G" Gracefully finishing, "I" Idle cleanup of worker, "." Open slot with no current process

We have Godaddy's Dedicated server. but we are facing problems with this server. after on 400-500 active users server randomly timeout or kill users. we this it's error with IIS. We did conversation with some server experts they said there is some issue with IIS. but nobody can resolve this issue. i share a screen shoot of analytic of active users. Please help us.


(counting $\sin x$ as a variation of $\cos x$).  They are self-similar in that their derivative is also a function of themselves. Crucially, this sort of feedback means that higher derivatives are also similar, resulting in curves that are smooth in what seems to me to be a unique way. For the examples in the title:  $f'(x) = f(x)$ is true for $f(x)=e^x$  $f'(x) = f(x+\pi/2)$ is true for $f(x)=\cos x$  EDIT: That's for the two functions given in the title. The question is: are there any other functions that are similar to their derivative in some other way? Just one example is enough (the "duplicate" doesn't address this).  BTW It seems to me that these are the only solutions to these differential equations, and e.g. a different offset for the second one just changes the period of the $\cos$ function. But I don't see how to show this - or even how to think about it.  BTW this was inspired by Euler's equation, relating $\cos, \sin,$ and $e$. I think the fundamental connection is that they all are self-similar, and the rest is clever bit-twiddling (like how integers alternate even/odd, and $f(x) = (-1)^x$ alternates positive/negative).

Let $f \colon \mathbb{R} \rightarrow  \mathbb{R}$ be a smooth function such that $$f'(x) = f(1+x)$$ How can we find the general form of $f$? I thought of some differential equations, but not sure how to use them here. Thanks.


How can gravitions exist without violating GR, since GR says that gravity is curvature in space-time.

As I'm reading about GR a lot lately, I was wondering: how do gravitons (if they exist ofc) impact the general relativity?  Since in GR, when we look at particles moving in space-time, we are only looking from geometric point of view so to say. Since gravity is represented with curvature of space-time via Einstein equations, we don't say gravity is a force that influences on bodies, gravity is just curvature affecting the bodies.  So if there is a graviton (gravitons) which would be mediators of gravity as a force within or not within the Standard Model, how would this be reconciled with the view of gravity as a curvature of space and time?  I would guess that this kinda question was asked by some scientists and answered, but I never really read anything on it. I don't even remember seeing gravitons mentioned in standard books about GR.  Are there any explanations about it?


I simply want two progress bar to increment simultaneously on a button click; i have created two progress bars and one button start with two threads t1 and t2 each of which contains different method in order to increment the values of two progress bars (t1 for progressbar1 and t2 for progressbar2 respectively).  Controls I have: Progress Bars: progressbar1, progressbar2 and Button button1.  The code is as follows:      Thread t1, t2;     private void Progressor1()     {         progressBar1.Minimum = 0;         progressBar1.Maximum = 100;          for (int i = 0; i <= 100; i++)                         progressBar1.Value = i;     }      private void Progressor2()     {                     progressBar2.Minimum = 0;         progressBar2.Maximum = 100;          for (int j = 0; j <= 100; j++)                         progressBar2.Value = j;                 }      private void button1_Click(object sender, EventArgs e)  // Start Button     {         t1.Start();         t2.Start();     }      private void MultiThreadedcs_Load(object sender, EventArgs e)// Form Load     {         t1 = new Thread(Progressor1);         t2 = new Thread(Progressor2);     }   At run time it shows me following error:     Error Name = InvalidOperationException   Error Message = Cross-thread operation not valid: Control 'progressBar2' accessed from a thread other than the thread it was created on.   Please help me out with this. I have less idea of threading concepts, i have gone through this solution with no progress in my problem:

I have a scenario. (Windows Forms, C#, .NET)   There is a main form which hosts some user control. The user control does some heavy data operation, such that if I directly call the UserControl_Load method the UI become nonresponsive for the duration for load method execution. To overcome this I load data on different thread (trying to change existing code as little as I can)   I used a background worker thread which will be loading the data and when done will notify the application that it has done its work.   Now came a real problem. All the UI (main form and its child usercontrols) was created on the primary main thread. In the LOAD method of the usercontrol I'm fetching data based on the values of some control (like textbox) on userControl.    The pseudocode would look like this:  CODE 1  UserContrl1_LoadDataMethod() {     if (textbox1.text == "MyName") // This gives exception     {         //Load data corresponding to "MyName".         //Populate a globale variable List<string> which will be binded to grid at some later stage.     } }   The Exception it gave was     Cross-thread operation not valid: Control accessed from a thread other than the thread it was created on.   To know more about this I did some googling and a suggestion came up like using the following code  CODE 2  UserContrl1_LoadDataMethod() {     if (InvokeRequired) // Line #1     {         this.Invoke(new MethodInvoker(UserContrl1_LoadDataMethod));         return;     }      if (textbox1.text == "MyName") // Now it wont give an exception     {     //Load data correspondin to "MyName"         //Populate a globale variable List<string> which will be binded to grid at some later stage     } }   BUT BUT BUT... it seems I'm back to square one. The Application again  become nonresponsive. It seems to be due to the execution of line #1 if condition. The loading task is again done by the parent thread and not the third that I spawned.  I don't know whether I perceived this right or wrong. I'm new to threading.  How do I resolve this and also what is the effect of execution of Line#1 if block?  The situation is this: I want to load data into a global variable based on the value of a control. I don't want to change the value of a control from the child thread. I'm not going to do it ever from a child thread.   So only accessing the value so that the corresponding data can be fetched from the database.


The contribution to the propagator from a particular trajectory is  $e^{\frac{iS[x(t)]}{ћ}}$. Does anyone knows how to get to this $e^{\frac{iS[x(t)]}{ћ}}$? As in showing me any reliable source regarding this because I try searching for how to come up with it but to no avail. Sorry for this stupid question as I just started.

In the book "Quantum Mechanics and Path Integrals" Feynman & Hibbs state that  the probability $P(b,a)$ to go from point $x_a$ at time $t_a$ to the point $x_b$ at the time $t_b$ is $P(b,a) = \|K(b,a)\|^2$ of an amplitude $K(b,a)$ to go from $a$ to $b$. This amplitude is the sum of contributions $\phi[x(t)]$ from each path. $$ K(b,a) = \sum_{\text{paths from $a$ to $b$}} \phi[x(t)]$$ The contributions of a path has a phase proportional to the action $S$: $$ \phi[x(t)] = \text{const}\ e^{(i/\hbar)S[x(t)]}$$  Why must the contribution of a path be $\sim e^{(i/\hbar)S[x(t)]}$? Can this be somehow derived or explained? Why can't the contribution of a path be something else e.g. $\sim \frac{S}{\hbar}$, $\sim \cos(S/\hbar)$, $\log(S/\hbar)$ or $e^{- (S[x(t)]/\hbar)^2}$ ? Edit: I have to admit that in the first version of this question, I didn't exclude the possibility to derive the contribution of a path directly from Schrödinger's equation. So answers along this line are valid although not so interesting. I think when Feynman developed his formalism his goal was to find a way to quantize systems, which cannot be treated by Schrödinger's equation, because they cannot be described in terms of a Hamiltonian (e.g. the Wheeler-Feynman absorber theory). So I think a good answer would explain Feynman's Ansatz without referring to Schrödinger's equation, because I think Schrödinger's equation can only handle a specific subset of all the systems that can be treated by Feynman's more general principle.


One definition of temperature I have seen is   $$T= \left(\frac{\partial E}{\partial S}\right)_N.$$  While $E, S, N$ each has clear meaning (internal energy, entropy, number of particles), I don't know how to interpret the subscript $N$.  Do I take an average among all particles or is there any other meaning?

What do we mean when we write $$\Bigg(\frac{\partial f}{\partial y}\Bigg)_x  $$ should $x$ in $f$ be considered constant every time after we take $\Big(\frac{\partial f}{\partial y}\Big)_x  $? So in particular is $$\frac{\partial}{\partial x}\Bigg(\frac{\partial f}{\partial y}\Bigg)_x =? \ 0 $$


Definition:  Let f(x) be a function defined on an interval that contains x=a, except possibly at x=a . Then we say that,if for every number ε>0 there is some number δ>0 such that $$\left| {f\left( x \right) - L} \right| < \varepsilon \hspace{0.5in}{\mbox{whenever}}\hspace{0.5in}0 < \left| {x - a} \right| < \delta$$  My question is whether I can change the def to the following 1): $$\left| {f\left( x \right) - L} \right| <= \varepsilon \hspace{0.5in}{\mbox{whenever}}\hspace{0.5in}0 < \left| {x - a} \right| <= \delta$$ 2): $$\left| {f\left( x \right) - L} \right| < \varepsilon \hspace{0.5in}{\mbox{whenever}}\hspace{0.5in}0 < \left| {x - a} \right| <= \delta$$ 3): $$\left| {f\left( x \right) - L} \right| <= \varepsilon \hspace{0.5in}{\mbox{whenever}}\hspace{0.5in}0 < \left| {x - a} \right| < \delta$$ If not, could you please provide an counter-example? It seems all ok to me. But I am not certain.

Definition (As written in Michael Spivak's Calculus)     The function $f$ approaches a limit $l$ near $a$ means: for every $\epsilon >0$ there is some $\delta > 0$ such that, for all $x$, if $0<|x-a|<\delta$, then $|f(x)-l|<\epsilon$.   my question is: why can't it be: $$0<|x-a|\leq \delta,|f(x)-l|\leq \epsilon$$ After looking at limits of functions for a long time just to grasp it's meaning and using the definition quite a lot solving homework I realized I keep writing the same inequality without really understanding why.  The only explanation given in Spivak's book for this part of the definition goes over it without explaining the inequality. I tried looking for an explanation myself but wasn't really able to find anything wrong with it. Is it also possible to write the definition like that or is there a problem with that?   (first non-homework related question :p)


As a corollary to a previous question:    Are there any precautions or cleaning methods that I have to take when cutting said naga chillis? I've had chilli linger on surfaces before but they were never this hot.

I made some habanero salsa last night for the first time (my god, was it delicious) and took care to clean everything that was used.  I figured I was good when I had no problems taking my contacts out afterwards.  So, fast forward to this morning.  The slap chop was still out to dry (stop having a boring pepper, stop having a boring life!) so I put it all away aand then found out the hard way when I went to put my contacts in that I did not in fact clean the tools well enough.  So, I've now got a slap chop, 2 knives and a cutting board which all need to be cleaned of the oils.  What's the best way to do this?  I can throw them all into the dishwasher at once if needed, none of the plastics should melt.


I have a crontab job running daily as a non-root user job. Unfortunately it did stop working with the following message (in /var/log/syslog):  CRON[29256]: Authentication token is no longer valid; new one required   I have not change a password for the user running this job, neither is password expired. What is causing this issue and how to fix it? - preferable without a need to change user's password every x days.  Ubuntu 14.04.1 LTS

The Setup:  1) The user's password was deleted with "passwd -d " command  2) The user has cron jobs running  The Problem: Once every 30 days (default password expiration policy) the cron fails with an error  Authentication token is no longer valid; new one required ERROR: failed to open PAM security session: Success ERROR: cannot set security context   My Questions: Is there a way to prevent this from happening? Why is the authentication token expired for a user with deleted password?


Assume the linear regression $Y=b_{0}+b_{1}X$ The $100(1-a)$% prediction interval for $x=x_{*}$ is given by  whereas the The $100(1-a)$% confidence interval for $E(Y|X=x_{*})$ is given by  What I don't understand is the difference in the shape of the bands. The upper and lower 100(1-a)% prediction intervals are straight lines, whereas the the 100(1-a)% confidence intervals for $E(Y|X=x_{*})$ are curves, with the minimum band width at $E(X)$ I understand the reasons why prediction bands are wider than the equivalent confidence bands. But, is there an intuitive way to understand why the shapes of the confidence and prediction bands are different?  The formulas are from

I have noticed that the confidence interval for predicted values in an linear regression tends to be narrow around the mean of the predictor and fat around the minimum and maximum values of the predictor. This can be seen in plots of these 4 linear regressions:    I initially thought this was because most values of the predictors were concentrated around the mean of the predictor. However, I then noticed that the narrow middle of the confidence interval would occur even if many values of were concentrated around the extremes of the predictor, as in the bottom left linear regression, which lots of values of the predictor are concentrated around the minimum of the predictor.  is anyone able to explain why confidence intervals for the predicted values in an linear regression tend to be narrow in the middle and fat at the extremes?


There is this extra 20gb of space in my Temporary Files that I can't seem to find. I have searched up on this issue and a lot of people says its the windows.old file but i can't seem to find that either

How can I visualize which folders and files are taking up all of the space on my hard drive?  I'm getting some conflicting reports on the size of hard drive contents. Namely what is and isn't there and what folders are actually using the space.   I need to know which of the files or folders the culprits behind all this hidden bloat. Also there should be a print option to get it on paper.


I'm trying to prove that isometries $T:\Bbb R^2\to\Bbb R^2$ are linear (usual Euclidean metric). It is assumed that $T(0)=0$. I think that I have proved that $T(\alpha v)=\alpha T(v)$, but I'm having problems with sum.  Context: I have defined $\Bbb R^2$ as a set of points and a set of free vectors.The dot product is like that $(a,b)\cdot(c,d)=ac+bd$ and the module of a vector $v$ is $\sqrt{v\cdot v}$. I have defined lines as set of points $\{P+t\vec v:t\in\Bbb R\}$. I have managed to prove triangular inequality. Just that.  My idea is proving that $$\|Tu+Tv-T(u+v)\|^2=0$$ but I get dot products like $Tu\cdot T(u+v)$. I have tried other expresions like $$\|T(u+v)-Tu\|^2,$$ getting the same problem. On the other hand, the trick $$u\cdot v=\frac12\left(\|u+v\|^2-\|u\|^2-\|v\|^2\right)$$ leads me to a circular reasoning, bacause I have to compute $T(u+v)$. Any ideas? Note: I can't deal with continuity in $\Bbb R^2$. This is for a High School student.

Suppose $f$ is an isometric (i.e., distance preserving) function on $\mathbb{E}^2$ such that $f(0,0) = (0,0)$.  Then I want to show that $f$ is necessarily linear.  Now $f$ is linear iff $f$ is both additive and homogenous.  The following is an attempted proof for the homogeneity of f (missing the last step); still more, I have no idea how to argue for the additivity of $f$.  Any ideas?  Let $x \in \mathbb{E}^2$ and $\alpha \in \mathbb{R}$   We know that $\forall x \in \mathbb{E}^2$, $\Vert x - 0 \Vert = \Vert f(x) - f(0)\Vert = \Vert f(x) - 0 \Vert$ so that $\Vert x\Vert = \Vert f(x)\Vert$.  From this we immediately have the following facts:  $\Vert x \Vert = \Vert f(x) \Vert$  $\Vert \alpha x \Vert = \Vert f(\alpha x) \Vert$  We can then argue that since $\Vert \alpha x\Vert = |\alpha| \Vert x \Vert = |\alpha| \Vert f(x) \Vert = \Vert \alpha f(x) \Vert$, we also have that $\Vert f(\alpha x) \Vert = \Vert \alpha f(x)\Vert$.  Finally, we have that  $\Vert \alpha x - x \Vert = \Vert \alpha f(x) - f(x) \Vert$   iff $ \Vert (\alpha - 1)x \Vert = \Vert (\alpha - 1) f(x) \Vert$   iff $|\alpha - 1| \Vert x \Vert = |\alpha - 1| \Vert f(x) \Vert$  Since the last of these statements is in fact true, we now have $\Vert \alpha x - x \Vert = \Vert \alpha f(x) - f(x) \Vert$ as desired.  Now at this point it seems like I have all of the facts required to assert that $f(\alpha x) = \alpha f(x)$, but I can't figure out how to formally state why without illegally appealing to visual intuition.  Any ideas?


I was updating the clamav antivirus defenitons with the sudo freshclam command and the output was:   ERROR: /var/log/clamav/freshclam.log is locked by another process ERROR: Problem with internal logger (UpdateLogFile = /var/log/clamav/freshclam.log).

I have the latest version of freshclam and clamav installed, and in the past (when I had Ubuntu 14.10) it has only run freshclam automatically a few times a day, but has not been running all the time. Now what I am finding though that if I go to Terminal and execute:  sudo freshclam   That I get:   ERROR: /var/log/clamav/freshclam.log is locked by another process ERROR: Problem with internal logger (UpdateLogFile = /var/log/clamav/freshclam.log).   And then the only way to be able to manually run that command is to kill the freshclam process, but this is time wasting, and annoying, so I would like to fully stop freshclam from auto updating, so that I can do manual updates.  So what I tried was to install , and in the Update Assistant settings I tried to set it so that I would manually install updates, and then I clicked Apply, but this seemed, even after a restart, to have no impact on how freshclam behaved.  So really my question is, how can I get it so that freshclam does not automatically check for updates, or at least for it to do it a few times a day, but not always be there so that I have to kill it to run it? Or is there a way to fix clamtk so that it does it properly (I have got in touch with the developer of clamtk and he is looking into it, but does not know what the issue is)?    OS Information:  Description:    Ubuntu 15.04 Release:    15.04   Package Information:  ClamTk:  clamtk:   Installed: 5.18-1   Candidate: 5.18-1   Version table:  *** 5.18-1 0         100 /var/lib/dpkg/status      5.15-1 0         500 http://gb.archive.ubuntu.com/ubuntu/ vivid/universe amd64 Packages   ClamAV:  clamav:   Installed: 0.98.7+dfsg-0ubuntu0.15.04.1   Candidate: 0.98.7+dfsg-0ubuntu0.15.04.1   Version table:  *** 0.98.7+dfsg-0ubuntu0.15.04.1 0         500 http://gb.archive.ubuntu.com/ubuntu/ vivid-updates/main amd64 Packages         500 http://security.ubuntu.com/ubuntu/ vivid-security/main amd64 Packages         100 /var/lib/dpkg/status      0.98.6+dfsg-1ubuntu2 0         500 http://gb.archive.ubuntu.com/ubuntu/ vivid/main amd64 Packages


I have a new MacBook Pro 2017, running OS 10.13.6 and I am afraid to shut down because I don't remember my password.  How do I find it or make a new one?

This is kind of an unusual question: a (non-technical) friend of mine (quite literally) on the other side of the world finds herself in the following situation:   A person died unexpectedly, their Mac is still running and displaying the Lock Screen, and nobody has the password nor any sort of technical expertise. They would like to get access to at least the data on the disk, maybe also the account. They are currently afraid to shut down the computer because it displays a warning about unsaved files.  Is there any chance they can get into the account from the Lock Screen? I guess not.  Failing that, what would be the easiest way to gain access to the data (after a forced reboot)? Single User Mode?


Prove: If $f:[a,b] \to \mathbb{R}$ is Riemann integrable, then $f$ is bounded.  My class did this using proof by contradiction and epsilon-delta definition (which I have hard time understanding).   Is there an alternative proof (perhaps easier)? Can someone explain the proof by contradiction method?   I did not post the class proof because it's way too long. Thanks.

Most statements regarding Riemann integrals (at least the ones that I have encountered) begin with the statement "for $f(x)$ bounded on $[a,b]$." I am wondering if Riemann integrability implies boundedness. I think that this has to be the case, but I am not sure. If Riemann integrability does imply boundedness, are improper integrals considered Riemann integrals? I would think that improper integrals wouldn't be Riemann integrals since improper integrals are allowed to be equal to $+\infty$ or $-\infty$. Or are improper integrals that are not equal to $\infty$ considered Riemann integrals?   I am confused.


New to python and having trouble with populating a list.  mat = [[0]*3]*4  for i in range(4):   for j in range(3):     mat[i][j] = (i,j)  print(mat)   The piece of code above prints out:  [[(3, 0), (3, 1), (3, 2)],  [(3, 0), (3, 1), (3, 2)],  [(3, 0), (3, 1), (3, 2)],  [(3, 0), (3, 1), (3, 2)]]   When I thought it should print out something like:  [[(0, 0), (0, 1), (0, 2)],  [(1, 0), (1, 1), (1, 2)],  [(2, 0), (2, 1), (2, 2)],  [(3, 0), (3, 1), (3, 2)]]   I realize this might be a simple question, but what am I doing wrong? Everywhere online tells me to populate a list this way as well.  Thanks in advance!

I needed to create a list of lists in Python, so I typed the following: my_list = [[1] * 4] * 3  The list looked like this: [[1, 1, 1, 1], [1, 1, 1, 1], [1, 1, 1, 1]]    Then I changed one of the innermost values: my_list[0][0] = 5  Now my list looks like this: [[5, 1, 1, 1], [5, 1, 1, 1], [5, 1, 1, 1]]    which is not what I wanted or expected. Can someone please explain what's going on, and how to get around it?


In a job interview, I want to ask the interviewer about work hours. We are talking in the present. In this case which sentence is correct, and why?        I was wondering, what are the work hours?   I am wondering, what are the work hours?

Why isn't the present tense used?     I am wondering if you would like to come for dinner.


Consider the following piece of code using the tikz-feynman package.  \begin{center}     \begin{tikzpicture}[baseline={(current bounding box.center)}]     \begin{feynman}         \diagram [vertical'=a to b] {             {   [edges={draw=none}]                 a -- b [label=0:\(\mu_{3}\)]                 -- c [label=-180:\(\mu_{4}\)]                 -- d [label=-180:\(\mu_{1}\)]                 -- a [label=0:\(\mu_{2}\)],             },             {   [edges={photon}]                 a -- ap [particle=\(p_{2}\)],                 b -- bp [particle=\(p_{3}\)],                 d -- dp [particle=\(p_{1}\)],                 c -- cp [particle=\(p_{4}\)],             },         };         \diagram* {             (c) -- [fermion] (b)                 -- [fermion] (d)                 -- [fermion] (a)                 -- (c),         };     \end{feynman}     \end{tikzpicture}     %     \feynmandiagram[baseline={(current bounding box.center)}, vertical'=a to b,] {         {   [edges={fermion}]             a -- [edge label=\(k+p_{1}+p_{2}\)] b [label=0:\(\mu_{3}\)]             -- [edge label=\(k-p_{4}\)] c [label=-180:\(\mu_{4}\)]             -- [edge label=\(k\)] d [label=-180:\(\mu_{1}\)]             -- [edge label=\(k+p_{1}\)] a [label=0:\(\mu_{2}\)],         },         {   [edges={photon}]             a -- ap [particle=\(p_{2}\)],             b -- bp [particle=\(p_{3}\)],             d -- dp [particle=\(p_{1}\)],             c -- cp [particle=\(p_{4}\)],         },     };     %     \begin{tikzpicture}[baseline={(current bounding box.center)}]     \begin{feynman}         \diagram [vertical'=a to b] {             {   [edges={draw=none}]                 a -- b [label=0:\(\mu_{3}\)]                 -- c [label=-180:\(\mu_{4}\)]                 -- d [label=-180:\(\mu_{1}\)]                 -- a [label=0:\(\mu_{2}\)],             },             {   [edges={photon}]                 a -- ap [particle=\(p_{2}\)],                 b -- bp [particle=\(p_{3}\)],                 d -- dp [particle=\(p_{1}\)],                 c -- cp [particle=\(p_{4}\)],             },         };         \diagram* {             (a) -- [anti fermion] (b)                 -- [anti fermion] (d)                 -- [anti fermion] (c)                 -- (a),         };     \end{feynman} \end{tikzpicture} \end{center}               It gives me the following output:    I would like to add a caption to each of these diagrams with the words 'Figure I,' 'Figure II' and 'Figure III' respectively.  How do I do so?

Consider the following piece of code, which uses the tikz-feynman package:  \usepackage{tikz-feynman, contour} \tikzfeynmanset{compat=1.1.0}  \begin{document} \begin{center}     \begin{tikzpicture}[baseline={(current bounding box.center)}]     \begin{feynman}         \diagram [vertical'=a to b] {             {   [edges={draw=none}]                 a -- b [label=0:\(\mu_{3}\)]                 -- c [label=-180:\(\mu_{4}\)]                 -- d [label=-180:\(\mu_{1}\)]                 -- a [label=0:\(\mu_{2}\)],             },             {   [edges={photon}]                 a -- ap [particle=\(p_{2}\)],                 b -- bp [particle=\(p_{3}\)],                 d -- dp [particle=\(p_{1}\)],                 c -- cp [particle=\(p_{4}\)],             },         };         \diagram* {             (c) -- [fermion] (b)                 -- [fermion] (d)                 -- [fermion] (a)                 -- (c),         };     \end{feynman}     \end{tikzpicture}     %     \feynmandiagram[baseline={(current bounding box.center)}, vertical'=a to b,] {         {   [edges={fermion}]             a -- b [label=0:\(\mu_{3}\)]             -- c [label=-180:\(\mu_{4}\)]             -- d [label=-180:\(\mu_{1}\)]             -- a [label=0:\(\mu_{2}\)],         },         {   [edges={photon}]             a -- ap [particle=\(p_{2}\)],             b -- bp [particle=\(p_{3}\)],             d -- dp [particle=\(p_{1}\)],             c -- cp [particle=\(p_{4}\)],         },     };     %     \begin{tikzpicture}[baseline={(current bounding box.center)}]     \begin{feynman}         \diagram [vertical'=a to b] {             {   [edges={draw=none}]                 a -- b [label=0:\(\mu_{3}\)]                 -- c [label=-180:\(\mu_{4}\)]                 -- d [label=-180:\(\mu_{1}\)]                 -- a [label=0:\(\mu_{2}\)],             },             {   [edges={photon}]                 a -- ap [particle=\(p_{2}\)],                 b -- bp [particle=\(p_{3}\)],                 d -- dp [particle=\(p_{1}\)],                 c -- cp [particle=\(p_{4}\)],             },         };         \diagram* {             (a) -- [anti fermion] (b)                 -- [anti fermion] (d)                 -- [anti fermion] (c)                 -- (a),         };     \end{feynman}     \end{tikzpicture}     \end{center} \end{document}   This piece of code draws the following figure:    I would like to label each figure. I do not want a caption, but just a label beneath each diagram. The label should say Diagram I, Diagram II, Diagram III.  How do I implement this into my code?


I'm not having any luck with Drush (just hangs) to update a (non-production) D8 site, dev branch (from around beta2) to Head.  How would one manually update the files db/config?

I'd like to create a website with Drupal 8 Alpha 3. But I'd like to know for sure if it's possible to do a harmless upgrade to Drupal 8 Beta once that it's released.  I heard something about the Drupal 8 API being frozen, but after reading this article () i'm not so sure anymore.  Can anyone help out?  PS: The website i'm going to build is fairly simple (few content-types, views, blocks etc)


When using quotes to notate a name or title of something, does punctuation go inside or outside the quote?  For example:   This approach is at the center of Harvard's research on "Learning in Action", which demonstrated that the best...  OR is it  This approach is at the center of Harvard's research on "Learning in Action," which demonstrated that the best...  I'm typing in a restricted template that doesn't allow for underlining or italics, so solely curious about where the comma goes.

The American convention in quotations is (typically) to place punctuation inside quoted text. But I always run into situations where the punctuation of the quote interferes with the punctuation of the sentence. How would you punctuate this (American, non technical)?     When my friends ask, "What do you want for your birthday?", I never know how to respond.   It seems odd to place the last comma outside the quote simply because of the question mark. Is that the preferred (i.e. most often accepted) standard?


I have two objects that I have already positioned into each other the way I'd like them to be. My question is how do I make them into one actual object, like they were made like that. Thank you.

I'm creating side skirts for a truck and I am duplicating the frames I want. The problem is it's making the duplicated object into another object. How do I put it into the same one?


I use Java 8.0 (IDE Eclipse). And sometimes want to drill-down into specific implementation (fields, methods) of which original developers (of language internals itself) have chosen.  In many times Wikipedia is too general (helps, but not enough), while other sources answer to just-near, but not exact my question.  And besides it - I am sometimes curious to see by myself (for both "want to be more independent" and "seeing by myself eyes is best to understand and be convinced" reasons).   How can I see inside, like this ?  My specific questions for now (as example and I ask to really know how-to): How internally random numbers generated in Java, I mean what the exact algorithm for output Java uses (using Math.random()) ?

I want to have a look at how Java implements LinkedList. Where should I go to look at the source code?


I would like to know how to prove that $$\prod_{r=1}^{(n-1)/2} 2\cos\frac{\pi r}{n}=1~~~~~\text{where $n$ is odd}$$ I have tried induction and using trigonometric identities to attempt to transform the product into something more helpful, but nothing has worked. It may be more helpful to think of the product as $$\prod_{r=1}^{n} 2\cos\frac{\pi r}{2n+1}=1$$ Many thansk for your help.

Evaluate $$ \prod_{r=1}^{7} \cos \left({\dfrac{r\pi}{15}}\right) $$  I tried trigonometric identities of product of cosines, i.e, $$\cos\text{A}\cdot\cos\text{B} = \dfrac{1}{2}[ \cos(A+B)+\cos(A-B)] $$ but I couldn't find the product. Any help will be appreciated. Thanks.


Since upgrading to Ubuntu 19.10 I cannot save files and links to the desktop. With Ubuntu 19.04 I used a GNOME extension called "Desktop icons" to do this but it doesn't work in 19.10. I can't find anything in the setup or GNOME Tweaks to enable this. The file ~/Desktop exists and still contains the files and folders which were on my 19.04 desktop.  Out of interest, why is it nowadays regarded as a bad thing to save things on the desktop? I still find it useful to put stuff I'm either working on or use a lot there.

After upgrading from 18.04 to 19.04 (with a necessary upgrade to 18.10 between) on a Lenovo Yoga 11e, I can no longer drag and drop anything (ie, files, windows, etc.) with the touchpad.  I can, however, move things around using the touchscreen.  Whenever I attempt to do so with the mouse, though, sometimes it turns into a hand.  Whether or not it turns into the hand or remains a pointer, the icon will not move anymore.  IOW, as soon as I left-click, the pointer freezes in place until I release the touchpad.


This is a follow-up question to .  I think the spacing issue happened when the equation number is greater than 9 (shown in the image). I tried to add a space with \vspace and \quad in \addcontentsline but it didn't work any one have a clue?

This is a follow up question of .  The formatting problem has nothing to do with cleanthesis.sty.  The problem is that if I use the charter font, page numbers greater than 99 are not formatted correctly in the table of content.  \documentclass[draft=on]{scrbook} \usepackage{blindtext} \usepackage{charter}  \listfiles  \begin{document} \tableofcontents \section{Section 1} \blindtext[100] \section{Section 2} \blindtext[500] \section{Section 3} \end{document}


My site has one IP. They set for me tww records into DNS servers: www.mydomain.com    -->  admin.mydomain.com  -->   My apache httpd.conf reads as follows:  ... ServerName www.mydomain.com:80 DocumentRoot "/home/somewhere/www"  NameVirtualHost <IP A>:80  <VirtualHost <IP A> >     ServerAdmin webmaster@mydomain     DocumentRoot /home/somewhere/www/admin     ServerName admin.mydomain.com  </VirtualHost>   Now, if I type www.mydomain.com or admin.mydomain.com I get the same page, i.e. the main server. The nslookup command shows that both www.mydomain.com and admin.mydomain.com point to IP A. Any help?

I have a VPS that I've installed a Apache Web Server on. What I want to do is forward my own website domains to that server and host those websites' files inside my Apache Web Server. As far as I understand a DNS server is required to manage which domain is hosted where (IP-wise). But what I want to do is host my websites under the same IP address, the one that my web server has. How can I separate those websites' files inside my web server so I don't have to use http://host/foo for www.foo.com and http://host/bar for www.bar.com?


I am using Javascript, and I'd like to make one IF statement that will check one variable against multiple strings using the least amount of code as possible. This is what I used: if (string == "1" || string == "2" || string == "3" || string == "4") { console.log("This should execute when string is 1, 2, 3, or 4"); }  How would I go about this same thing with the least amount of code as possible? I am using Javascript.

What is the most concise and efficient way to find out if a JavaScript array contains a value? This is the only way I know to do it: function contains(a, obj) {     for (var i = 0; i < a.length; i++) {         if (a[i] === obj) {             return true;         }     }     return false; }  Is there a better and more concise way to accomplish this?


Hisoka's Nen ability is . It creates a flexible substance that sticks to objects and makes them pullable at demand.      I don't understand how Hisoka made that exam participant's arms disappear in episode 3 (2011 series). Can you please explain it?

In the first Hunter Exam of the series (Hisoka's second),  was introduced into the series removing another applicant's arms from his body for bumping into him and not apologizing.    What did he actually do? We know Hisoka's abilities are Bungee Gum and Texture Surprise, but they don't explain how the arms are converting into flower petals as seen above.


I need help with the following proof, which my professor added for practice (but not as homework). I am completely lost here.  Let $A$ be a nonempty subset of a metric space $X$. Define $d(\cdot ,A) : X \to [0,\infty)$ by  $$d(x,A) = \inf\{d(x,a) : a \in A\}.$$   Prove that $d(\cdot,A)$ is continuous.   Now there are some things that I do know.    The definition of continuous:Suppose X,Y are metric spaces, a ∈ X and f : X → Y. The function f is continuous at a if for every ε>0there is a δ>0such that if dX(a,x) < δ, then dY (f(a),f(x)) < ε.  If f is continuous at every point a ∈ X, then f is said to be continuous.  The following theorem:A function f : X → Y is continuous if and only if f−1(U) ⊂ X is open for every open set U ⊂ Y .

Let $(X,d)$ be a metric space. How to prove that for any closed $A$ a function $d(x,A)$ is continuous - I know that it is even Lipschitz continuous, but I have a problem with the proof:  $$ |d(x,a) - d(y,a)| \leq d(x,y) $$ for any $a\in A$ - but we cannot just replace it by $|d(x,A) - d(y,A)|\leq d(x,y)$ since the minimum (or infimum in general) can be attained in different points $a\in A$ for $x$ and $y$, so we only have that $$ |d(x,A)-d(y,A)|\leq d(x,y)+\sup\limits_{a,b\in A}d(a,b) $$ which does not mean continuity.


I am flying from A to B, with a connecting flight through London Heathrow (i.e. A -> LHR -> B). Both flights are with the same company/conglomerate, and so my bags will still be in transit (and not with me).   I have a 10 hours wait in LHR and want to go downtown and do some substantial shopping (including alcohol). I plan to buy another suitcase, fill it with these shopping, and then dropping at the bag drop, so I can have it at my final destination.   Is it possible to do this? Can I add another suitcase in one of my flight connections?

A common desire among some travelers with long layovers is to leave the airport for a while, and perhaps do some shopping, or even buy goods in the airport.  But this then often necessitates the ability to check additional luggage during the layover, for the remainder of the journey.  There might be other reasons to want to check luggage mid-journey as well.  Are there any general rules one can use to determine whether this is an option in a given airport when traveling with a given airline, and the associated costs (when it is possible)?


My new Ubuntu Dell laptop version 12.04 is not playing videos.   I get the error message,  mpeg-4 aac codec not installed   I can't install the ubuntu-restricted-extras package  Here is the error message:  -Vostro-3546:~# sudo apt-get install ubuntu-restricted-extras Reading package lists... Done Building dependency tree        Reading state information... Done E: Unable to locate package ubuntu-restricted-extras   I get the same error when I try to install any package.

I would like to install the restricted extras package, which I didn't select during the install. How can I do that?        is a meta-package that installs:         Support for MP3 and unencrypted DVD playback   Microsoft TrueType core fonts   Flash plugin   codecs for common audio and video files


In  there is this Statement:       shall take Care that the Laws be faithfully executed     Now I want to know whether "be" can or should be replaced by "are", and why is it not in the said Statement.

We will make the convention that exact categories be skeletally small.   Is this construction (used in a mathematical context) correct? There is something that strikes me as odd in that "be". Should it be "are"? I know I've seen a similar way of using "be" like that, without conjugating the verb, but I'm not completely sure when it should be used.


What's the easiest/fastest way of calculating the determinant of $$\begin{pmatrix}a & b & c & d\\ -b & a & -d & c\\ -c & d & a & -b \\ -d & -c & b & a\end{pmatrix}$$? The result is $(a^2+b^2+c^2+d^2)^2$. This determinant occurs in Zarhin's trick (if $A$ is an Abelian variety, $(A \times A^t)^4$ is principally polarised).

I need to calculate the following determinant in order to prove the following equality:  $$\det\begin{pmatrix} a & b & c & d \\ -b & a & -d & c \\ -c & d & a & -b \\ -d & -c & b & a \end{pmatrix} = (a^2+b^2+c^2+d^2)^2.$$  I tried using Gauss-algorithm to get an easier matrix, but I'm not sure if I did it correctly.  Calling the $4$ lines $I$, $II$, $III$ and $IV$, I did:  (1) $II \cdot a$  (2) $III \cdot a$  (3) $IV \cdot a$  After this I did:  (4) $II' + I \cdot b$  (5) $III' + I \cdot c$  (6) $IV' + I \cdot d$  So finally I got the following matrix:  $$\begin{pmatrix} a & b & c & d \\ 0 & a^2+b^2 & bc-ad & ac+bd \\ 0 & ad+bc & a^2+c^2 & cd-ab \\ 0 & bd-ac & ab-cd & a^2+d^2 \end{pmatrix}.$$  I thought this would make the determinant a bit easier, unfortunately I must have done something wrong. Is multiplication with single lines allowed as I have done it?  Thank you very much.


I have been confused by different interpretations of polynomial and monomial. Is $\sqrt[3]{x^3}$ really a monomial?

Are $(x^3)^{1/3} $ and $\sqrt{x^2}$ monomials?    In mathematics, a  is, roughly speaking, a polynomial which has only one term. Two different definitions of a monomial may be encountered:  For the first definition, a monomial, also called power product, is a product of powers of variables with nonnegative integer exponents, or, in other words, a product of variables, possibly with repetitions.   For the second definition, a monomial is a monomial in the first sense multiplied by a nonzero constant, called the coefficient of the monomial.


I installed Ubuntu bash on my windows machine, so I can test linux scripts away from work.  I created a very simple script with basic "hello world" and a change directory (cd), but when executing it displays the hello world.  It errors out on the cd to directory line.   Here is the error:  $ ./test.sh hello world zipping away ./test.sh: line 6: cd: $'/home/fjaffer/temp\r\r': No such file or directory ./test.sh: line 7: $'\r': command not found ffr@DP-PC:~$   My script test.sh is below:     #!/bin/bash echo "hello world" echo "zipping away" dir=/home/fjaffer/temp cd $dir   Please advise? Thank you.

I'm getting an error in WSL while trying to use .  I followed all the install steps successfully on Windows 10 x64 using the steps at , then Ubuntu for Windows with GitHub desktop .  But I'm blocked at the latest steps.  It's where I trying to download or train the model in Windows. Using for example the Ubuntu Linux prompt, I navigate manually to the appropriate place and type a following command like the one below (I also tried in su mode)  bash pretrained_models/download_pix2pix_model.sh facades_label2photo   I get an immediate error, always the same, similar to these:  root@Azure:/mnt/c/Users/vincent/Downloads/vision/pytorch-CycleGAN-and-pix2pix# bash pretrained_models/download_pix2pix_model.sh facades_label2photo pretrained_models/download_pix2pix_model.sh: line 2: $'\r': command not found Note: available models are edges2shoes, sat2map, and facades_label2photo pretrained_models/download_pix2pix_model.sh: line 4: $'\r': command not found ]pecified [facades_label2photo pretrained_models/download_pix2pix_model.sh: line 6: $'\r': command not found mkdir: cannot create directory ‘./checkpoints/facades_label2photo\r_pretrained\r’: No such file or directory pretrained_models/download_pix2pix_model.sh: line 10: $'\r': command not found WARNING: timestamping does nothing in combination with -O. See the manual for details.  : No such file or directoryhphoto pretrained_models/download_pix2pix_model.sh: line 12: $'\r': command not found pretrained_models/download_pix2pix_model.sh: line 13: $'\r': command not found   Any idea?


I often use String.Empty for a placeholder, which equates to "".  So my question, why does a const not like String.Empty?  They compile identically.  // Good private const string example = "";  // Bad private const string example = String.Empty;   What in String.Empty makes it not able to be used with a const.

In .NET, what is the difference between String.Empty and "", and are they interchangable, or is there some underlying reference or Localization issues around equality that String.Empty will ensure are not a problem?


So, I need help with this question, it has been posted on this site before but I couldn't understand it, here it is.  Annabel made a shape by placing identical square tiles in a frame as shown in the diagram above. The tiles are arranged in columns. Each column touches the base but no columns touch the side or top. There are no empty gaps between columns. The frame can be enlarged as needed. D. Show four arrangements of 137 tiles, each arrangement with a different maximum height, so that the ant walks a total of 34 tile edges.  Thanks in advance

I've been having a problem with these problems for a week now so I thought I'd post it on MSE. Read the text below. . I've also typed it up:  Annabel made a shape by placing identical square tiles in a frame as shown in the diagram above. The tiles are arranged in columns. Each column touches the base but no columns touch the side or top. There are no empty gaps between columns. The frame can be enlarged as needed.  These are the questions. I've also typed them up.    A. Show that it is possible to arrange $7$ tiles so that the ant walks $8,9,10,11,12,13,14,15$ tile edges.   B. Show 6 ways of arranging 7 tiles so that the ant walks a total of 9 tile edges.  C. Show it is possible to arrange 49 tiles so that the ant walks a total of less than 21 tile edges.  D. Show four arrangements of 137 tiles, each arrangement with a different maximum height, so that the ant walks a total of 34 tile edges.  For question $a$, is there a formula relating the number of tile edges exposed to the number of tiles. These are my answers for $a$    For the above picture, it's the left hand side which has the $a$ answers.  However, I'm having a bit of trouble with $b$. I've already got four answers down but where are the other two. My four current answers are in the right hand side of the last image. Also, I'll also appreciate a formula to show the relationship.  I'm also having trouble with $c$. I found out that you get 21 tile edges exposes when you make a $7*7$ square but the answer is asking for less than 21. Can anyone help me. Also, as in the previous questions, a formula to show the relationships would be great.  And for $d$, I am totally lost. I have no idea where to start, and I certainly can't find out four arrangements. So can anyone help me? And as always, a formula is nice  P.S. Please explain this in an understandable formula, as I'm only a Year 7 with the ability to understand linear algebra and parts of quadratics and trigonometry. Also, sorry about the poor imaging.


If I am taking a cruise starting from Rome and covering only Schengen countries. Is single entry Schengen visa adequate for the trip

Do I need a single entry or a multiple entry Schengen if I am travelling on a Disney cruise that starts in Barcelona and then calls on ports in France then Italy?


Which sentence is the correct one, or are they both correct?   I am going to the post office in 2 hours. Shall I post the letter for you? or I will be going to the post office in 2 hours. Shall I post the letter for you?

Would you please tell me which tenses are suitable here?  ... the sun (KEEP) burning forever? Sometime in the next twenty-five years, a spaceship with a human crew (LAND) on Mars.  My grammar book gives only two options: "to be going to + verb" and "will + verb". But I wonder the reason why I should avoid using the "continuous present" tense.


What are the various ways to reach Hogwarts School of witch craft and wizardry from the muggle world? Is Kings Cross Platform 9-3/4 the only way to reach Hogwarts from the Muggle world?

Everyone familiar with Harry Potter is likely familiar with the Hogwarts Express, the direct line from Kings Cross station in London to Hogsmeade. But being a direct line, this would seem to require everyone who wanted to use it to first travel to London.  Assuming Hogwarts is the only school for students aged 11+ local to England (i.e. Hogwarts isn't just for London locals), are there alternative conventional (Muggle) means of getting students from other parts of the country to Hogwarts or Hogsmeade?


i have an XML file, I recovered from ftp. i want to convert this xml to json i use the xml2json   How can I call an external command  from within a Python script?  python script:  #!/usr/bin/env python  import ftplib import os  # Connection information server = 'xxxxxx.xxxx' username = 'xxxxxxxx' password = 'xxxxxxxx'  # Directory and matching information directory = '/datas/' filematch = '*.xml' src='/opt/scripts/' dst='/opt/data/'  # Establish the connection ftp = ftplib.FTP(server) ftp.login(username, password)  # Change to the proper directory ftp.cwd(directory)  # Loop through matching files and download each one individually for filename in ftp.nlst(filematch):     fhandle = open(filename, 'wb')     print 'Getting ' + filename     ftp.retrbinary('RETR ' + filename, fhandle.write)     fhandle.close()  #?????????????????? EXECUTE XML2JSON TO CONVERT MY XML INTO JSON ??????????????????????? #?????????????????? xml2json -t xml2json -o stockvo.json stockvo.xml --strip_text ?????????????  #move the stockvo.xml file to destination os.system('mv %s %s' % (src+'stockvo.xml', dst+'stockvo.xml'))  #remove the src file  os.unlink(src+'stockvo.xml')

How do you call an external command (as if I'd typed it at the Unix shell or Windows command prompt) from within a Python script?