Comprehensive factorization and universal I-central extensions in the Mal'cev c...

• Author(s): Bourn, Dominique ; Rodelo, Diana
• Date: 2010
• Persistent ID: http://hdl.handle.net/10316/13716
• Origin: Estudo Geral - Universidade de Coimbra
• Subject(s): Regular Mal'tsev category; Birkho subcategory; Comprehensive factorization; Central extension
• Document Type: Preprint
• Language: English

Description

We show that, under suitable left exact conditions on a re ection functor I, the construction of the associated universal I-central extension is reduced to the comprehensive factorization of a speci c internal functor. This observation produces some existence conditions which hold in particular for any re ection from a Mal'cev variety to any Birkho subvariety