I've read Near-duplicate or “subset” proposals on Area51 and understand the "wait and see" process that @Robert C. is suggesting. I have had some comments on my proposal, Algorithms and Data Structures suggesting that it is a subset of Theoretical Computer Science. If the community at large feels they should be merged, I do not oppose the merger.

However, since the merge was suggested, the Algorithms proposal has been gaining a larger group of followers (albeit far fewer than TCS) . My only concern is that Theoretical Computer Science does not suggest the practical aspect of using algorithms and designing data structures. In my opinion, there is a big difference between theory and practicality.

So, I am interested in what the community has to offer as far as how these two proposals should be handled.

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    How much overlap is there in the users? That could be a problem if they're fractured across the two very similar proposals.
    – random
    Jul 12, 2010 at 19:03
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    they seem pretty related, and Lance's suggestion of using tags to differentiate seems good
    – warren
    Jul 12, 2010 at 20:17
  • @random: that is a good question. Is there a way to do pull that data?
    – IAbstract
    Jul 14, 2010 at 21:48
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    TCS sounds similar to "algorithms and data structures" but in fact it's not really -- the "Theoretical" part isn't just fluff, TCS != CS. TCS is a small, highly mathematical field that is a level of abstraction up from regular CS, just as writing a program to sort a list of numbers is a level above just sorting a particular list of numbers. TCS is about finding relationships (e.g. reducibility) between and properties (e.g. running time lower bounds) of all algorithms. Asking a question about a particular algorithm on a TCS forum would be like asking "What is 4 + 9?" on MO. Dec 29, 2010 at 4:14

7 Answers 7


The A&DS proposal claims that it will cover questions at risk of being off topic for SO, but none of the 6 questions currently with 10+ on-topic votes would be in any danger of being counted off topic on SO.

Given that [algorithms] is a top-20 tag on SO, I don't see that the proposal has made much case for being independent of SO.

I agree with dboar that TCS and A&DS as the proposal now stands are not close enough to justify a merge.

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    I agree that many of the questions would not be off-topic on SO. As a matter of fact, I don't think of them would really be off-topic. Obviously, I expect the proposal process to work as intended. We are getting a lot of followers, and the questions are increasing. I also feel that the quality of questions is improving. My biggest issue with merging A&DS with TSC is that there is a big difference between theory and practical use. I would be much more likely to agree that A&DS is a subset of SO than TSC.
    – IAbstract
    Jul 13, 2010 at 17:33

You might be interested in reading the thread on meta.mathoverflow.net about inviting in the TCS community. http://tea.mathoverflow.net/discussion/498/bringing-theorycs-over-to-mathoverflow/

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    I think it makes sense to either merge TCS with Algorithms or merge TCS with MO, but it certainly doesn't make sense to do both. This is a question for the TCS people. Unfortunately it seems that with the current Area51 setup there's no easy way to communicate with the people committed to TCS to find out what they want. Jul 13, 2010 at 3:15
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    @Noah, I read most of that thread and I agree - it would not be appropriate for A&DS to merge with TCS if TCS is attempting to merge w/ MO. I would be disappointed if I pushed for a merge only to get lost in TCS/MO.
    – IAbstract
    Jul 13, 2010 at 17:56

Theoretical CS and A&DS though essentially the same have been differentiated by software developers. Software developers would never want a question like this:

How does the Mulmuley-Sohoni geometric approach to producing lower bounds avoid producing natural proofs (in the Razborov-Rudich sense)? 21 on-topic votes on Theoretical CS

but can bear with

I want to write a program to solve a maze. How should I do it ? 25 off-topic votes on Theoretical CS

But Computer scientists can find both of them useful. I just want to say that we software developers do not want all the stuff that we wouldn't use practically. I am against this merger.


my concern with A&DS was a lack of focus on what questions were in scope vs out of scope. I agree that Theoretical Computer Science and A&DS could end up covering different communities (the former being closer to MO and the latter being closer to SO), but neither are progressing up the food chain that quickly anyway.


I feel that completely practical question are on-topic for SO, research-level question about algorithms and data structures are for TCS.SE, and non-research-level questions about algorithms and data structures are for Math.SE. I personally don't understand how the two top voted on-topic questions: "Can you explain the difference between NP-Hard and NP-Complete?" or "Why can't a comparison-based sort be less than O(n log n)?" can be considered a practical algorithmic/data structure question. I think the supporters of the proposal should give examples of on-topic questions which will distinguish the proposal from already existing related sites by being off-topic on all of them. I don't think it is a good idea to start a new site if it will not cover a reasonable amount of questions which are not covered on already existing sites.

We see a some amount of cross-posting between MO, TCS, Math.SE, SO. (I don't not know the official view of SE people on having multiple copies of question on different sites when a user is trying to maximize the chance of getting an answer.)

Having too many sites will divide users and question, it will drain users from already existing sites and there won't be serious communities. I feel that people follow and commit to the proposals when they are interested in the proposed topic and without considering whether having a new site for the topic is a good idea.

ps: I think in long term the SE people need to find a better way of reducing the duplicate copies on different sites and increasing the coordination between them.

Here is an idea: we can think of each site as a view and questions on each site as a super-tag combining the copies of the question and the answers from different sites in one place and letting users see only the answers having specific super-tags. Deleting a question from a site will remove the corresponding super-tag. I think in that case having largely overlapping sites should not be a problem. I am sure there are lots of things that SE people have to consider and the this is not a through thought idea.

  • I have the same feeling about Crypto.SE, the research-level theoretical questions are for TCS.SE and MO, the non-research-level theoretical questions for Math.SE, ad the practical question for SO and Security.SE.
    – Kaveh
    Dec 28, 2010 at 7:52

I vote for merging them, then using tags to differentiate concepts.

  • [theory] vs [practical] ...???
    – IAbstract
    Jul 12, 2010 at 23:55
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    -1: merging with TCS would be worse than closing the proposal as duplicating SO. Jul 13, 2010 at 18:15

I agree that theoretical concepts and practical implementation are both very different things, but practical implementation is not possible without understanding theoretical concepts, and theory will be useless if it cannot be implemented practically. So, I think that both proposals should be merged. And questions related to both theory and practical should be discussed on the same site.

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    "practical implementation is not possible without understanding theoretical concepts" - I'm guessing that, because of the difference in the people interested in the respective proposals, the theoretical concepts discussed by the TCS folks won't be at all useful to the practical questions raised by the A&DS folks. The research-level aims of TCS make it a better fit for MO, while I don't see a case that SO doesn't already serve the purposes of the A&DS proposal very well. Jul 15, 2010 at 8:12

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