Title
Facets of descent, I
Abstract
An elementary topological approach to Grothendieck's idea of descent is given. While being motivated by the idea of localization which is central in Sheaf Theory, we show how the theory of monads (=triples) provides a direct categorical approach to Descent Theory. Thanks to an important observation by Bénabou and Roubaud and by Beck, the monadic description covers descent also in the abstract context of a bifibred category satisfying the Beck-Chevalley condition. We present the fundamentals of fibrational descent theory without requiring any prior knowledge of fibred categories. The paper contains a number of new topological descent results as well as some new examples in the context of regular categories which demonstrate the subtlety of the descent problem in concrete situations.
Year
DOI
Venue
1994
10.1007/BF00878100
Applied Categorical Structures
Keywords
DocType
Volume
18C20,18A40,18A20,18D30,54B40,54C10,Descent data,(effective) descent map,monad,monadic functor,fibred category,Beck-Chevalley condition,étale-descent
Journal
2
Issue
ISSN
Citations 
3
0927-2852
17
PageRank 
References 
Authors
18.87
2
2
Name
Order
Citations
PageRank
George Janelidze14033.99
Walter Tholen27739.38