Tag Archives: synchronization

Birthday conferences

The impending removal of my university web pages has led me to put here the slides of some talks. I have been extremely fortunate in having wonderful colleagues who have organised three birthday conferences for me. (Well, one was actually … Continue reading

Posted in doing mathematics, events | Tagged , , , , , | Leave a comment

The Hall–Paige conjecture

A Latin square of ordern is an n×n array of symbols from an alphabet of size n with the property that each symbol in the alphabet occurs once in each row or column. Two Latin squares L and M are … Continue reading

Posted in doing mathematics, exposition, mathematics | Tagged , , , , , , , , , | 2 Comments

RA position in St Andrews

We are looking for a postdoctoral research assistant on the project “Bi-synchronizing automata, outer automorphism groups of Higman–Thompson groups, and automorphisms of the shift”. The Principal Investigator is Collin Bleak; I am the co-I. The project involves an interesting mix … Continue reading

Posted in Uncategorized | Tagged , , , , , , | Leave a comment

Synchronization and all that, 2

The story I told in the last post is not over. The recent development is that we spotted a mistake in the paper. An easy mistake to make: we had simply used the symbol n in two different places with … Continue reading

Posted in doing mathematics, exposition | Tagged , , , , , , , , | Leave a comment

Synchronization and separation in the Johnson schemes

Today a paper by Mohammed Aljohani, John Bamberg and me went on the arXiv on this topic. Here is a brief summary of what it is about. Synchronization comes in several flavours, and the point of the paper is to … Continue reading

Posted in exposition, Uncategorized | Tagged , , , , | Leave a comment

A week in Vienna

Last week, in the second week of Spring break in St Andrews, I was in Vienna, giving a course of lectures to the PhD students, at the invitation of Tomack Gilmore, a Queen Mary undergraduate now finishing his PhD with … Continue reading

Posted in events, Lecture notes, Uncategorized | Tagged , , , , , , , , | 4 Comments

Automorphism groups of transformation semigroups

I have been in the transformation semigroups game for nearly ten years now, but I still feel that I am finding my feet. Here is apparently a huge difference between permutation groups and transformation semigroups, one which is still not … Continue reading

Posted in doing mathematics, open problems, Uncategorized | Tagged , , | Leave a comment

The Higman–Thompson groups

I celebrated the last day of spring last week with the appearance of two substantial papers on the arXiv: one with Maria Elisa Fernandes, Dimitri Leemans, and Mark Mixer, proving that the maximum rank of a regular polytope whose group … Continue reading

Posted in exposition | Tagged , , , , , , , | 7 Comments

ACCMCC, Days 4 and 5

Penny Haxell opened proceedings on Thursday with her astonishing work with Ron Aharoni. They give a sufficient condition for a tripartite 3-uniform hypergraph (one whose vertex set is partitioned into three parts so that each hyperedge contains one vertex from … Continue reading

Posted in events | Tagged , , , , , , | 1 Comment

Permutation groups and transformation semigroups

When I first decided to apply to the LMS to run a Durham symposium on Permutation Groups and Transformation Semigroups, I had a fairly clear idea of what I wanted: topics (both finite and infinite) where the techniques and results … Continue reading

Posted in Uncategorized | Tagged , , , , , , , , , | Leave a comment