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# Tag Archives: strongly regular graphs

## Equitable partitions of Latin square graphs

On our recent trip to Shanghai, Rosemary Bailey and I met Sergey Goryainov, who gave a talk about some joint work with his supervisor Alexander Gavrilyuk at the International Workshop on Bannai–Ito Theory in Hangzhou. I mentioned it in my … Continue reading

Posted in Uncategorized
Tagged eigenvalue, equitable partition, Latin squares, quotient matrix, strongly regular graphs
1 Comment

## Advanced Combinatorics: the St Andrews lectures

Three years ago, when I joined the School of Mathematics and Statistics at the University of St Andrews, it was suggested that I might like to give a final year MMath module on “Advanced Combinatorics”. No compulsion. Well, of course … Continue reading

Posted in Lecture notes
Tagged Catalan numbers, chromatic polynomial, cycle index, doocot principle, enumeration, formal power series, Friendship Theorem, Gaussian coefficients, generalised line graphs, generalised quadrangles, IBIS groups, line graphs, Mathieu groups, matroid, Moebius inversion, orbit-counting lemma, projective planes, root systems, strongly regular graphs, symmetric Sudoku, triangle property, Tutte polynomial, weight enumerator
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## Guessing numbers of graphs

A paper, “Guessing games on triangle-free graphs”, by Anh Dang, Søren Riis, and me, has just appeared in the Electronic Journal of Combinatorics. Here is a brief discussion of what it is about. It is always a pleasant surprise when … Continue reading

## London Combinatorics Colloquia

This week saw the two linked London Combinatorics Colloquia, at Queen Mary and the London School of Economics. Not so long ago, a one-day meeting in Reading organised by Anthony Hilton was a fixture of the calendar. When Anthony came … Continue reading