16 Dezembro 1997, 15:30
Walter Tholen, York University
An axiomatic setting for separation and compactness

Depending on a class of 'closed' morphisms, there are natural categorical notions of separation and compactness, which have been studied intensively in particular when 'closed' means 'closed with respect to a closure operator'. In this talk we present a system of more general axioms on a class of 'closed' morphisms, which still allow us to establish a satisfactory finite theory of separation, compactness and perfectness, and to present a number of new examples in topology and algebra. We shall also comment on Diers' Zariski closure of algebraic sets in our context..