Take the 2-minute tour ×
MathOverflow is a question and answer site for professional mathematicians. It's 100% free, no registration required.

Let $G$ and $Cay(A,S)$ be strongly regular graphs with the same parameters. Is it true that $G$ is a cayley graph?

share|improve this question

1 Answer 1

up vote 6 down vote accepted

no, this is certainly not true. IIRC already on 25 vertices there is a family of 15 non-isomorphic s.r.g.'s with the same parameters, some of them Cayley graphs, some not: see http://www.win.tue.nl/~aeb/graphs/Paulus.html.

share|improve this answer
2  
Latin square graphs (e.g. cs.yale.edu/homes/spielman/561/2009/lect23-09.pdf) will work; for each possible order there is a Cayley graph and (in general, $n\ge5$) examples that are not. –  Chris Godsil Dec 21 '12 at 13:48
4  
For anyone who decides, as I did, to do a google search to find out the meaning of IIRC, ignore the entries on the "Illinois Interactive Report Card" and on the "International Integrated Reporting Council". –  Lee Mosher Dec 21 '12 at 15:41
4  
It means "Isn't It Really Cool" –  Brendan McKay Dec 23 '12 at 10:53
    
Yes, Brendan, this would work too :-) –  Dima Pasechnik Dec 23 '12 at 15:03

Your Answer

 
discard

By posting your answer, you agree to the privacy policy and terms of service.

Not the answer you're looking for? Browse other questions tagged or ask your own question.