Computer Science is the study of the theory behind computation. How is this (beta) subdomain different than cstheory.stackexchange.com? Shouldn't they be merged?

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    $\begingroup$ I think the main difference is that CSTheory is only for research-level questions. $\endgroup$
    – Juho
    Aug 24, 2012 at 9:50
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    $\begingroup$ TCS SE faq answers your question. $\endgroup$
    – Nobody
    Aug 24, 2012 at 10:05
  • $\begingroup$ So CSTheory is for Grad level topics, and this one is for undergrad then? $\endgroup$ Aug 24, 2012 at 10:09
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    $\begingroup$ CSTheory is for research-level questions in theoretical computer science. This site is for any question in computer science, generally excluding questions about programming. See our faq. $\endgroup$ Aug 24, 2012 at 10:33
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    $\begingroup$ I guess that cstheory.stackexchange is where theoretical questions can be asked. cs.stackexchange is where cs questions can be asked (theory included). $\endgroup$
    – mrk
    Aug 24, 2012 at 12:02
  • $\begingroup$ If you have used the correct way of creating an account the system should have notice that and allowed you to associate it with your other accounts. You have probably used different information/openid. ps: this has already been discussed on meta so you should have find the answer if you searched. $\endgroup$
    – Kaveh
    Aug 24, 2012 at 14:23
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    $\begingroup$ See also How to make our cs community very different from the cstheory? $\endgroup$ Aug 24, 2012 at 15:08
  • $\begingroup$ @Kaveh What is the "correct way" to create an account? I've only used the same ID (Facebook) for every subdomain I've visited. $\endgroup$ Aug 25, 2012 at 2:05
  • $\begingroup$ @Travis, there are two possibilities: either there is a bug in the software or you have done it incorrectly. I think the first one is less likely. What you have done incorrectly I don't know. It works correctly for other users. $\endgroup$
    – Kaveh
    Aug 25, 2012 at 4:00
  • $\begingroup$ @Travis, it seems to me that your account is associated with your other accounts on the network. You don't have +200 rep on any of them and therefore start with +1 rep on cs.se. You cannot post on meta because you don't have enough reputation and that is by-design. $\endgroup$
    – Kaveh
    Aug 25, 2012 at 4:06
  • $\begingroup$ @Kaveh Someone has pointed out the 200 rep limit for this feature to me now, but I wanted to make sure you weren't trying to warn me about some pitfall I was oblivious to. Thanks. $\endgroup$ Aug 25, 2012 at 19:34

1 Answer 1


Theoretical Computer Science is a site for research-level questions in theoretical computer science, as the FAQ clearly states.

Computer Science is a site for computer science at all levels, whether theoretical or applied. Again, see the FAQ: this is a site for students, researchers and practitioners of computer science.

Computer Science encompasses both theoretical and applied science: both semantics of programming languages and compilation, both process calculi and network modeling, both graph theory and analysis of social graphs, both computational geometry and computer graphics, …

The topic of Theoretical Computer Science is a subset of Computer Science. This isn't to mean that every question on TCS would be ok on CS, as TCS's more specialist community allows questions that are considered “non constructive” on a site with a broader audience. Also, while research-level questions in theoretical computer science are on-topic on CS, they are better-suited on TCS where they are more likely to meet a specialist audience. TCS and CS have overlapping but separate communities.

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    $\begingroup$ I still maintain that CS itself is the theory of computation so applying "Theory" to CS is redundant. After reading the FAQs (thanks for the links - it's hard to know where to find info when you're new) it seems clear that CSTheory is for Graduate and PhD level discussions and CS is for "students, researchers and practitioners" implying undergrad and application. Since I just have a Bachelors in CS, I'll color inside the lines and stay over here instead of embarrassing myself over there. $\endgroup$ Aug 25, 2012 at 2:12
  • $\begingroup$ @Travis, you are free to think as you like but theoretical computer science is an established terminology as are other areas of computer science which are not part of theoretical computer science. I am sure you are not suggesting that we abandon the standard terminology used by Computer Scientists just because you have a different opinion. In any case, if you want to learn more I suggest starting by checking the wikipedia articles on TCS and CS. $\endgroup$
    – Kaveh
    Aug 25, 2012 at 3:55
  • $\begingroup$ @Kaveh I agree that it is common to use the term CS as an umbrella term for many topics. Oftentimes people say Computer Science when they mean Computer Programming. Such turmoil is common when a language is developing new terms for new concepts but things sort themselves out in the end. (And ~50 years is a short time when language is concerned.) See my answer to Gilles' post in Area 51. $\endgroup$ Aug 25, 2012 at 19:45
  • $\begingroup$ @Travis, sorry but you don't seem to be a computer scientist and it seems to me that you really don't have a good grasp of what people called computer scientist do. In any case, I am not going to argue about what should be the meaning of the term "computer science", you are free to think as you like. I think the difference of the scope between the sites is clearly explained by Gilles and others. $\endgroup$
    – Kaveh
    Aug 25, 2012 at 20:40
  • $\begingroup$ @Travis It will help, when communicating with others, if you use the standard definition of the words rather than your own. I suggest reading the Wikipedia article to see what other people mean by the term computer science. $\endgroup$ Aug 25, 2012 at 21:24
  • $\begingroup$ @Kaveh, when I first started getting my CS degree, I thought as you describe but over time my perspective changed. I'm not trying to argue with anyone. You'll see that I accepted Gilles' answer, but just added the comment that the terminology is redundant in order to distinguish it from casual use of the term for things that are better described with other terminology. $\endgroup$ Aug 25, 2012 at 21:59
  • $\begingroup$ @Gilles, I did in fact read that article and others before posting the question, which confirmed my perspective and the need for the question. As I'm new to SE, when I posted the question I didn't know how to find a description of each subdomain in its FAQ. Just because something is common usage, doesn't mean it's proper usage (and yes I also use the term CS colloquially when another term is proper, but not used as commonly). $\endgroup$ Aug 25, 2012 at 22:15
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    $\begingroup$ @Travis There is a difference between what real practitioners (i.e. people working in companies building software) call theory -- namely all things academic -- and what academics call theory -- namely the more mathematical part of the field. You could also say "physics is about the theory behind engineering" which would be a correct statement in many ways, but you would have to acknowledge that "theoretical physics" != "physics" (which includes e.g. experimental physics). For CS, it's similar. $\endgroup$
    – Raphael
    Aug 26, 2012 at 19:49
  • $\begingroup$ @Raphael AH! THAT is illuminating. I'd always thought of it more like math with theorems (academic theory) that are proven true/false than like theoretical physics with speculative models to be tested. How come I can't vote up your comment (as it appears to clarify most of the rest of the page)? $\endgroup$ Aug 26, 2012 at 20:41
  • $\begingroup$ @Travis: Glad I could help. :) Well, there is TCS with the math-style definition-theorem-proof structure, and there is also the hunt for abstract models that better describe CS "reality". The point is that there are plenty of (academic) computer scientists who don't care at all for the mathy or the (abstract) model-finding parts; they want to achieve tangible results. (I guess you can't upvote because of low rep.) $\endgroup$
    – Raphael
    Aug 27, 2012 at 9:42
  • $\begingroup$ @Raphael I understand and agree with your physics vs. theoretical physics comment. I don't understand your "mathy" one above. Would you elaborate a little on "tangible results"? Or give an example to illustrate what you mean by that? Thanks. $\endgroup$
    – Nobody
    Aug 27, 2012 at 11:45
  • $\begingroup$ @scaaahu: Complexity theory is mathy. So is rigorous algorithm analysis. Developing an algorithm and benchmarking it (often called algorithm engineering) is not. Designing an efficient cache coherence protocol is (probably) not, either. There are shades of gray here, obviously; you can do many things in in a formal, rigorous way or in a hand-waving way, for instance design and definition of a programming language. $\endgroup$
    – Raphael
    Aug 27, 2012 at 12:09
  • $\begingroup$ @Raphael: Thanks. I understand and agree with your point now. $\endgroup$
    – Nobody
    Aug 27, 2012 at 12:31
  • $\begingroup$ @raphael "There is a difference between what real practitioners (i.e. people working in companies building software) call theory -- namely all things academic -- and what academics call theory -- namely the more mathematical part of the field." have seen this similar sentiment elsewhere but have also seen arguments against it. dont think anyone would be able to find an actual ref that supports it. imho its just off-the-books bias bordering on discrimination.... moreover TCS.se recently modified/widened charter to be more open to practitioners via eg "application-of-theory" tag $\endgroup$
    – vzn
    Sep 5, 2012 at 15:18
  • $\begingroup$ @raphael "Complexity theory is mathy. So is rigorous algorithm analysis. Developing an algorithm and benchmarking it (often called algorithm engineering) is not." but benchmarking is still a highly scientific and quantitative activity. moreover there are significant areas of empirical TCS. so what goes as quality or scope delimiters around here (both SE groups, TCS/cs!) seems at times like intellectual hairsplitting and angels dancing on heads of pins. travis, the real answer is that the charters are not consistent & are still evolving... both groups have low traffic now! merge someday? $\endgroup$
    – vzn
    Sep 5, 2012 at 15:21

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