One of the best things about being a mathematician is the opportunity to travel. I have kept various travel diaries . I play the guitar. Here is my latest picture of the density spectrum of random sum-free sets . See another photograph of me in the School photo gallery, and my Graph Theory White Pages entry .
More pictures are in the picture gallery .
J , the all-1 matrix. It is easy to see that symmetrizing a homogeneous coherent configuration gives a Jordan scheme. Old problems from my homepage are kept with annotations. I also have a small list of permutation group problems , as well as problems from previous British Combinatorial Conferences . For a far more extensive collection of unsolved problems and links, see Steven Finch's Unsolved Mathematics Problems on the MathSoft site.