I have not kept up with the field very well, but I can recommend these works: Peter Johnstone, *Sketches of an Elephant*, Vol. 2, OUP 2003: the chapter on sketches. (I am in rural Wisconsin at the moment asnd don't have access to the book. If OUP would make its pages available to look at on Amazon I could have told you the exact page.) Bagchi and Wells, *Graph Based Logic and Sketches*, here: http://arxiv.org/PS_cache/arxiv/pdf/0809/0809.3023v1.pdf Also Kinoshita, et al 1997, referred to in GBLS. There might be relevant papers since 1993 mentioned in the Elephant, too. Category people: If you can suggest other papers that should be included, let me know soon, and I will revise the sketches paper to include them (and the ones I mentioned above). Charles Wells On Wed, May 20, 2009 at 4:23 PM, <Andre.Rodin@ens.fr> wrote:
Dear Charles and others:
this
http://www.cwru.edu/artsci/math/wells/pub/pdf/sketch.pdf
is your very useful overview of Sketch theory dated back to 1993. I wonder how much it omits today: are there significant research programmes in this field emerged during last 15 years? What should I look at first of all? Many thanks in advance.
Andrei