Open AccessDiextensions et panextensions de catégories
Author(s) -
Georges Hoff
Publication year - 2003
Publication title -
mathematica scandinavica
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.553
H-Index - 30
eISSN - 1903-1807
pISSN - 0025-5521
DOI - 10.7146/math.scand.a-14411
Subject(s) - mathematics , functor , quotient , kernel (algebra) , context (archaeology) , pure mathematics , commutative property , point (geometry) , algebra over a field , geometry , geography , archaeology
Considering some different notions of kernel for a quotient functor, news kinds of extensions of (small) categories appear. In each context, one sees how 2-cocycles are naturally defined. Classical 2-cohomologies, like Hochschild's one (for which the need of commutativity is here discussed), are particular cases in this framework. One has thus an unifying point of view for extensions structures.