Dear Colleagues, Since this is the categories list, I could and should have been more specific about the contents of the preprint I announced yesterday: "Topological representation of the lambda-calculus", available from my page on the WWW, http://www.andrew.cmu.edu/user/awodey/ In a nut-shell, the point is that the Butz-Moerdijk spatial covering theorem for topoi can be used to embed any CCC fully and faithfully (and CC) into a topos of sheaves on a space. So the "topological semantics" mentioned are actually in such topoi of sheaves. Steve A.