Preprint available (Fiore, Plotkin, and Turi).

The following preprint Abstract Syntax and Variable Binding by M.Fiore, G.Plotkin., and D.Turi. is available as http://www.dcs.ed.ac.uk/~dt/abstractsyn.ps Synopsis: We show that categorical algebra in the object-classifier topos provides a suitable mathematical universe for modelling algebraic structures with binding operators.