new address etc

I will be here at Oxford until 30 May. Oege de Moor, in the Computing Laboratory here, would like to know if every endofunctor on the category of sets preserves weak pullbacks. Any information on this would be appreciated. More generally, he is interested in lifting functors to the category of relations. Both he and I would like to know of papers written on this subject. --Charles Wells Subject Re: new address etc