Smallest non-isomorphic strongly regular graphs - MathOverflow most recent 30 from http://mathoverflow.net 2013-06-18T05:14:50Z http://mathoverflow.net/feeds/question/39312 http://www.creativecommons.org/licenses/by-nc/2.5/rdf http://mathoverflow.net/questions/39312/smallest-non-isomorphic-strongly-regular-graphs Smallest non-isomorphic strongly regular graphs Hans Stricker 2010-09-19T16:25:25Z 2010-09-19T18:23:51Z <p><strong>Motivation</strong>: I want to see how the 3-dimensional Weisfeiler-Lehman algorithm (see <a href="http://arxiv.org/PS_cache/arxiv/pdf/1003/1003.4865v1.pdf" rel="nofollow">Logical complexity of graphs</a>, p. 14) distinguishes between two non-isomorphic <a href="http://en.wikipedia.org/wiki/Strongly_regular_graph" rel="nofollow">strongly regular graphs srg(v,k,λ,μ)</a> in a specific example.</p> <blockquote> <p><strong>Question</strong>: What are the smallest non-isomorphic strongly regular graphs with the same v,k,λ,μ?</p> </blockquote> http://mathoverflow.net/questions/39312/smallest-non-isomorphic-strongly-regular-graphs/39319#39319 Answer by Andrew D. King for Smallest non-isomorphic strongly regular graphs Andrew D. King 2010-09-19T18:23:51Z 2010-09-19T18:23:51Z <p>This page <a href="http://www.maths.gla.ac.uk/~es/srgraphs.html" rel="nofollow">http://www.maths.gla.ac.uk/~es/srgraphs.html</a> lists some strongly regular graphs on few vertices, and gives two (16,6,2,2) graphs (which I didn't check but I presume they're non-isomorphic). I imagine they're the smallest possible but I haven't checked: <a href="http://www.maths.gla.ac.uk/~es/16.vertices" rel="nofollow">http://www.maths.gla.ac.uk/~es/16.vertices</a></p>