I am very confused about whether to post these types of question on Stack Overflow or Computer Science.SE.     I am aware Computer Science is in beta and would like to support it (constructively), I am also studying computer science. However, my questions are usually about coding specifics, but when it is about a programming principle, which site to I go to?
There seems to be more than a few computer science/programming Stack Exchange networks (is that the correct term?). Stack Overflow, being the first, has by far the most users, questions, and answers.  What is the reasoning for creating the others, and are there clear guidelines for which kinds of questions should be posted? I can see a large amount of potential overflow, many cases of people not getting a good answer to their question, because the person who has the answer isn't browsing that particular network at the moment.  I understand that they were probably created for organizational purposes, but wouldn't it almost make more sense to just have them as categories under Stack Overflow, keep them separated but still connected, instead of making people have to create multiple 'account's, one for each network?  I am sure there was a very good reason to break them up, but as someone that is new to SE, it can be somewhat intimidating to decide which one to post in to ensure you get a good answer. For example, if I am a computer science student, my first instinct might to be to post in the computer science network, until I see that it literally has 1% of the users as the Stack Overflow network, which still seems to be for programming/computer science related questions.  So my second instinct would then to be to post it into the Stack&nbsp;Overflow site on the basis that I have a significantly higher chance of my question being seen and getting a good answer. Then I notice that there is also a 'programmers' network, and I don't even begin to know where that fits in. I, and I am assuming most people, will probably just post on Stack&nbsp;Overflow to be safe.  My question is, other than the short little description blurb of each one, is there a clear cut set of guidelines which what each network is intended for, what kinds of questions should go to each one, and is anything being done to encourage people to post in these newer, smaller (more specialized?) networks as opposed to just posting in big daddy Stack Overflow?  Now again, this is for computer science/programming/"why isn't this code doing what I want?" related questions, I am not saying that if I had a question about Linux or WordPress or something I would have the same confusion.
Where is the usage of Ubuntu cloud guest image on OpenStack documented? I would very much like that the the appendix sections of the Table of Contents doesn't have a section numbers, dots, and page numbers. If I do the following  \documentclass{article} \usepackage{tocloft} \addtocontents{toc}{\cftpagenumbersoff{section}} \renewcommand{\cftdot}{} \begin{document} \tableofcontents \newpage \section{Appendix} \section*{Another Letter} \addcontentsline{toc}{section}{Another Letter} \end{document}   then the section "Another Letter" is left aligned, so it doesn't look like the  others.  Question  Is it possible to have "Another Letter" styled the same way as normal TOC entries, but just without section number, dots, and page number? "Communicate over" vs. "communicate through" Also schemas can communicate over database links to schemas in other remote databases.    Could one replace the preposition over with through? Will it change the meaning, and if so, when should we use over instead of through? After the training phase, is it better to run neural networks on a GPU or CPU? My understanding is that GPUs are more efficient for running neural nets, but someone recently suggested to me that GPUs are only needed for the training phase. Once trained, it's actually more efficient to run them on CPUs.  Is this true? Why does logging in to Stack Overflow keep me signed in to my Gmail email after logging out and regardless of the Stay signed in checkbox?  Steps to reproduce:   Browse to  and confirm you are logged out Browse to  and confirm you are logged out Click login Click Google Enter Email/Password and confirm Stay signed in is unchecked Click Sign in Click logout (up top) Click Logout (down below) Browse to  and confirm you are still logged in Click Sign out &lt;- Shouldn't clicking Logout on Stack Overflow be doing the same thing as this? Browse to  and confirm you are logged out     Answers are making sense but my frustration is that clicking Logout (twice) on StackOverflow essentially does nothing. If I proceed to click login and Gmail I am immediately authenticated because I still have an active Gmail cookie. In order to effectively logout I need to click Logout twice on Stack Overflow and then manually browse to  and Sign out. In a multi server architecture, is it possible to find out from which machine a user logged into current machine using ssh?  For example, user1 logged into host1. From there, the user logged into host2 as sruser using ssh.  In above example, would it be possible to trace the sruser session of host2 back to user1 session in host1?  Would it be possible to get the hostname or terminal of user1 session? Prove ${n - 1 \choose k - 1} + {n - 2 \choose k - 1} + {n - 3 \choose k - 1} + \dots + {k - 1 \choose k - 1} = {n \choose k}$ What finite groups always have a square root for each element? English (other than American English) has a clear differentiation between the two words. Both are about translocating something. In "bring" the something of somebody is moved to where the speaker is currently situated. "Take" is used to translocate something or somebody to a place that the speaker is not currently at.   You cannot “bring” your books to school if you are currently at home. You can only take them to school. Most of the time one can get the meaning from the context of the sentence but it can get very confusing when the other party is on the telephone and you do not know their location.   Why does American English not differentiate and when did it lose the differentiation? Can virtual particle have mass? Do all virtual particle travel at light speed in a vacuum? else wouldn't that imply they should have rest mass however tiny? When they pop back out of existence do their mass disappear instantly? BTW what is the heaviest virtual particle ever found? $1+x+\ldots+x^n$ perfect square Let $p$ be the polynomial $p(x)=1+x+\ldots+x^n$. For which couples $(a, n)\in\mathbb{N}^2$, $p(a)$ is a perfect square? I'm particularly interested in $p(3)$. Why do archery arrows tilt downwards in their descent? How can I find out if someone really holds a doctoral degree? We're currently interviewing candidates at my company and I'd like to verify if some of them really have the academic degrees they claim. One in particular claims a doctoral degree from a German university.  I've contacted the university, and the dean wrote back saying that they could not provide this information without the written consent of the individual.  I found this policy rather odd; I would have thought that the granting of a doctoral degree was public information. Is this normal? Is there anything else I can do to find out?  I obtained from the library a copy of the thesis in question but it was in German. I also found through Google  which appears to be a list of dissertations published by that university, but it is unclear whether these are doctoral dissertations or not. The person in question and his dissertation are in that list. How can I find $\gcd(a^m+1,a^n+1)$ with $a,m,n$ positive integers? How can I find $\gcd(a^m+1,a^n+1)$ with $a,m,n$ positive integers?    I have this idea:  Let $d=\gcd(m,n)$. Then there exist positive integers $x,y$ such that $mx-ny=d$ (WLOG). We shall find $G=\gcd(a^m+1,a^n+1)$.  If $m,n$ are odd, then $d$ is odd, therefore one and only one of $x,y$ is even. We have:  $$a^{ny}(a^d+1)=a^{mx}+a^{ny}=(a^{mx}-1)+(a^{ny}+1)=(a^{mx}+1)+(a^{ny}-1).$$  If $x$ is even and $y$ is odd, then $a^{m}+1\mid a^{mx}-1$ and $a^{n}+1\mid a^{ny}+1$, therefore $G\mid a^{ny}(a^d+1)$. If $x$ is odd and $y$ is even, then $a^{m}+1\mid a^{mx}+1$ and $a^{n}+1\mid a^{ny}-1$, thus $G\mid a^{ny}(a^d+1)$. However, since $\gcd(a^m+1,a^{ny})=\gcd(a^n+1,a^{ny})=1$, so $\gcd(G,a^{ny})=1$, hence $G\mid a^d+1$. We also have $a^d+1\mid a^{m}+1$ and $a^d+1\mid a^{n}+1$, so $a^d+1\mid G$. Thus $G=a^d+1$.  If $v_2(m)=v_2(n)=v_2(d)=k&gt;1$, then there exist some odd numbers $m_1,n_1,d_1$ such that $m=2^km_1,n=2^kn_1,d=2^kd_1$. We shall have $m_1x-n_1y=d_1$, so one and only one of $x,y$ is even, and we can use the same argument when $m,n$ are odd, so $G=a^d+1$.  However, if $v_2(m) \neq v_2(n)$, I cannot find any solutions for this. I think that $G \in \{1,2\}$, but I cannot prove or disprove it. How can I find $G=\gcd(a^m+1,a^n+1)$ if $v_2(m) \neq v_2(n)$ ? Moreover, is there anything from my arguments that can be improved ? The new profile shouldn't mistakenly imply that you can earn the Informed badge on a meta site I just joined Sports, and I decided to take a look on Sports Meta. I clicked on my profile there. This is part of what I saw:     Yet the profile shouldn't indicate that it is, in theory. . .  This seems to be a bug. Lattices are congruence-distributive Can Cycles use multiple UV layers? General relativity (gravitation) in time and one spatial dimension I don't have any idea of general relativity but intend to learn. Is it a good idea to study general relativity in two dimensions (time and single spatial dimension) in the begining to get good idea on the subject? If it is, then please give some references for such a treatment. How do I get my Mac to boot from an Ubuntu USB key? If you select "USB" and "Mac" on , it gives a series of command line instructions to make a USB key which the MacBook will boot into Ubuntu from.  I've followed them to the letter two or three times on different USB keys, and it doesn't work. There's a very great deal of technical discussion about EFI etc. but this set of instructions seems to suggest it should just work, but it doesn't.  Help? I'm increasingly unhappy with the more locked-down approach Apple is taking, and I'd quite like to start using Linux with a view to transitioning over to using it as my main operating system, but booting from the CD takes forever, runs slowly and I'm really hoping to get it moving off USB.  Can anybody help me? I know that I can create/burn bootable CD/DVD or live USB and can boot/install from it. But suppose I am currently running GNU/Linux and I've ISO file of another GNU/Linux that I want to install on my hard disk, then Can I directly boot from ISO from hard disk and try/install that GNU/Linux operating system?