strongly regular graph as two-graph - MathOverflow most recent 30 from http://mathoverflow.net 2013-06-20T02:17:15Z http://mathoverflow.net/feeds/question/96320 http://www.creativecommons.org/licenses/by-nc/2.5/rdf http://mathoverflow.net/questions/96320/strongly-regular-graph-as-two-graph strongly regular graph as two-graph mj125 2012-05-08T10:26:11Z 2012-05-10T10:50:52Z <p>is any strongly regular graph a regular two-graph?</p> <p>two-graph:a two graph is a collection $B$ of 3-subsets a set $X$ with the property that, for any 4-subset $Y$ of $X$, an even numbers of $B$ belong to $Y$.</p> <p>regular two-graph:a two-graph is regular if it is a 2-design (with parameters $2-(n,3,\lambda)$ for some $\lambda$ )</p> http://mathoverflow.net/questions/96320/strongly-regular-graph-as-two-graph/96337#96337 Answer by gordon-royle for strongly regular graph as two-graph gordon-royle 2012-05-08T13:50:29Z 2012-05-08T13:50:29Z <p>No, there is a correspondence between certain strongly regular graphs and two-graphs but those strongly regular graphs have specific and restricted parameters. </p> http://mathoverflow.net/questions/96320/strongly-regular-graph-as-two-graph/96562#96562 Answer by mj125 for strongly regular graph as two-graph mj125 2012-05-10T10:50:52Z 2012-05-10T10:50:52Z <p>ok, that's right, if $\Gamma$ is strongly regular graph with parameters $(v,k,\lambda,\mu)$ then it's regular two-graph if and only if $k=2\mu$</p>