Talk:Graph isomorphism

message: There seems to be a need to start this discussion. The article badly needs a more or less comprehensive review of available software for testing graph isomorphism. Here is just a couple of reasons for that:
# Testing graph isomorphism is of great practical importance; despite the uncertainty about its theoretical complexity, people still want to solve this problem in practice.
# Even if the worst case is hard to solve, many problem instances are easy and can be resolved by simple heuristics (e.g., the most trivial perhaps is comparison of the number of vertices of two graphs).
I started the section Software today but to my surprise some trolls immediate came into play and started deleting my additions without any explanation. Well, one of my items was indeed not that suitable for Wikipedia (thanks to Twri for pointing that out) but the others perfectly make sense.
David Eppstein deleted my recent addition of a link to Combinatorica package for Mathematica CAS, motivating that it is "not primarily about isomorphism and would be several positions down on a list of notable isomorphism implementations". I believe that is not a legitimate reason for deletion since:
# This is a reputable package for widely used Mathematica CAS.
# This packages contains functions for testing/finding graph isomorphism and that makes it very relevant to including into Software section of Graph isomorphism article. It may be not "not primarily about isomorphism" as it contains a bunch of other discrete mathematics related functions, but that does not neglect its abilities of solving graph isomorphism problems.
# The statement about benchmarking is also an irrelevant argument: first, it is subjective without an appropriate citation; second, even if this package is not a state-of-art tool for graph isomorphism problems, it is still useful for many problems of this kind (and many users of Mathematica).
Based on the above explanation, the link to Combinatorica package should be restored in Software section. Maxal (talk) 00:18, 3 March 2009 (UTC)
replies: text: The primary objection is adding external links without addition of encyclopedic content, especially about software and packages. Wikipedia is a repository of encyclopedic information about notable things described in reliable sources. A mere link to any software package is useless from these points of view and often look dubious: after all, people can use google themselves to find out what else in on web.  I agree that a section about implementations is badly missing. And a proper solution would be to add it, to describe implementations other people (besides authors, friends and family members) think notable and state so in published materials. In particular, in the case at hand, if it is  known which algorithm is implemented in Mathematica, then it may be briefly mentioned here. Otherwise a ref to Mathematica is of low relevance: it has thousands of functions, but we are not going to include external links to Mathematica into thousands of wikipedia articles. - 7-bubёn >t 00:35, 3 March 2009 (UTC)
replies: text: The authors of Combinatorica are respected scientists, there is a book published about solving problems with the Combinatorica package - isn't that all make this packages "notable"? Maxal (talk) 00:42, 3 March 2009 (UTC)
replies: text: It may be notable as a software package in general and yet not sufficiently notable in the much more specific context of implementations of graph isomorphism algorithms. —David Eppstein (talk) 00:55, 3 March 2009 (UTC)

text: But it is notable enough for Mathematica users etc. Anyway, these all are still just subjective opinions. The facts are: it is a notable package, it is able to solve (some) graph isomorphism problems; and that makes it relevant for mentioning it in the current Wikipedia article. Maxal (talk) 01:07, 3 March 2009 (UTC)

text: (Edit conflict) See our guidelines on external links, regarding what sorts of links include: “A well-chosen link to a directory of websites”. We already include such a well-chosen link, to Skiena's SUNYSB listing of graph isomorphism implementations. Therefore, we don't need to duplicate the contents of that link ourselves: Wikipedia is not a web directory. Additionally, it seems against our policies on maintaining a neutral encyclopedia to push for the inclusion of this link, for a package of routines for a specialized commercial piece of software (Mathematica) that only includes isomorphism as one among a large number of other routines, and not to push for links to highly-regarded packages that are specific to graph isomorphism such as Nauty. (For more on the relative significance of these different implementations, the ratings on the SUNYSB site might be relevant.) I continue to feel that the link to Combinatorica should not be included: there are five more-deserving links included on the SUNYSB list, and including all of them would head more towards being an indiscriminate web directory than being an encyclopedia. —David Eppstein (talk) 00:36, 3 March 2009 (UTC)
replies: text: I don't see why a link to Skiena's should prevent from mentioning various "notable" software implementations in Wikipedia article. Also notice that the package Combinatorica is not commercial itself (it is run under commercial Mathematica software but that does not make it commercial; and Mathematica is already described in Wikipedia). Links to other reputable software implementations are welcome as well. And there are not so many of them, so the article won't be "directory of websites" even if we include them all. Maxal (talk) 00:53, 3 March 2009 (UTC)

text: *Actually, Combinatorica is commercial, and not particularly a particularly good implementation of a graph isomorphism algorithm.  (I'm a Mathematica user, and I cannot use Combinatorica without purchase.)  — Arthur Rubin  (talk) 01:31, 3 March 2009 (UTC)

text: That's a non-sense. The package is freely available for download from the official website and distributed in the form of plain text Mathematica source code. Moreover, its header mentions the following licence:
 This package may be copied in its entirety for nonprofit purposes only.
 Sale, other than for the direct cost of the media, is prohibited.  This
 copyright notice must accompany all copies.
Maxal (talk) 02:00, 3 March 2009 (UTC)
replies: text: *The link to Skiena's explains that Mathematica uses Combinatorica package for GI, hence a separate link to Mathematica is redundant and constitutes an inexact credit. - 7-bubёn >t 01:31, 3 March 2009 (UTC)

text: The purpose of mentioning Mathematica is to indicate that the package won't run without it (i.e., this package is not a standalone application). Maxal (talk) 02:04, 3 March 2009 (UTC)
replies: text: Software I develop will not run without Microsoft Foundation Classes, yet my company does not put Microsoft in the first lines of its ad brochures. Hey, even with Microsoft it will not run without Intel chips. There is a healthy intellectual property threshold, and I don't believe it is inside Mathematica, rather than outside it, unless you present a solid proof otherwise.   - 7-bubёn >t 02:16, 3 March 2009 (UTC)

text: I explained why I gave a link to Mathematica - but I would not care if it is not mentioned at all. It is more important that Combinatorica package (and similar software) should be listed in the article. Maxal (talk) 02:21, 3 March 2009 (UTC)
replies: text: <sigh>. Let me reiterate: you may list anything you want sufficiently relevant, provided the you supply your additions with references to independent reliable sources which speak for notability and relevance of the software in question. These are among the most fundamental rules governing the content of wikipedia. A simple addition of external links to software packages does not conform these rules. - 7-bubёn >t 02:30, 3 March 2009 (UTC)

text: Oh, I see now what you meant under "link to Mathematica". A brief search discovered, in particular, a book about teaching discrete math in high school; and a book about randomness in physics that both explicitly mention Combinatorica's graph isomorphism testing function IsomorphicQ. I bet there other similar references exist. Maxal (talk) 02:58, 3 March 2009 (UTC)
thread_title:  Software review 

message: I suggest to file a formal complaint against Tim32, since it appears that he persistently refuses to accept the local consensus. Despite all arguments seen above, there is no evidence of the possibility of peaceful resolution. I cannot do it myself, since I am not well versed in wikilawyerese, but I will second the motion. - 7-bubёn >t 20:21, 3 March 2009 (UTC)
replies: text: If the problems with Tim32 continue, I recommend consulting Wikipedia:Mediation Cabal, where some informal dispute resolution could occur. Dcoetzee 19:34, 10 March 2009 (UTC)
replies: text: The edits of User:Tim32 on this page look like self-promotion to me. That falls under the 'promotional editing' clause of our Conflict of Interest guideline, which is explained under WP:COI#Blocks. I think that we are getting close to the point where Tim32 should be given a final warning against inserting reference to his own work into Wikipedia articles. EdJohnston (talk) 20:28, 10 March 2009 (UTC)
thread_title:  Tim32 behavior 

message: There is a good paper from 1977 summing up approaches to graph isomorphism until then, search for "The Graph Isomorphism Disease" from Ronald C. Read and Derek G. Corneil.  — Preceding unsigned comment added by 134.93.143.232 (talk) 11:29, 11 October 2013 (UTC)
replies: text: It is about Graph isomorphism problem; listed there, too - Altenmann >t 08:32, 8 January 2014 (UTC)
thread_title:  Good, reliable source 

message: *https://www.sciencenews.org/article/new-algorithm-cracks-graph-problem
--Kmhkmh (talk) 01:48, 13 November 2015 (UTC)
thread_title: possible breakthrough to watch out for

message: The definition as stated applies only in the context where graphs have no parallel edges.  This is a lot of people's favourite definition of "graph", but it is not universal.  See Graph (discrete mathematics).  FWIW I prefer "graph" to be able to include parallels and loops, and "simple graph" to be without loops or parallels.  Andrew Kepert (talk) 23:47, 6 December 2018 (UTC)
thread_title:  Fix definition?