14 Jan
1998
14 Jan
'98
10:58 p.m.
Date: Wed, 14 Jan 1998 16:21:51 +0000 (GMT) From: Tom Leinster <T.Leinster@dpmms.cam.ac.uk>
Is the pullback of a monadic functor along a monadic functor necessarily monadic?
No. And I seem to remember this was one of the main points of the thesis (under Lawvere) of Michel Thie'baud. The thesis title was "Self-dual structure-semantics & algebraic categories" (Dalhousie University, Halifax, Nova Scotia, August 1971). Comonads (= cotriples) in Mod (= Bimod = Prof = Dist) are the subject. Using these to define "algebraic", Michel obtained stability under pullback. --Ross