Semidirect Products and Split Short Five Lemma in Normal Categories

In this paper we study a generalization of the notion of categorical semidirect product, as defined in [6], to a non-protomodular context of categories where internal actions are induced by points, like in any pointed variety. There we define semidirect products only for regular points, in the sense...

Full description

Bibliographic Details
Main Author: Martins-Ferreira, Nelson (author)
Other Authors: Montoli, Andrea (author), Sobral, Manuela (author)
Format: article
Language:eng
Published: 2014
Online Access:http://hdl.handle.net/10316/44054
Country:Portugal
Oai:oai:estudogeral.sib.uc.pt:10316/44054
Description
Summary:In this paper we study a generalization of the notion of categorical semidirect product, as defined in [6], to a non-protomodular context of categories where internal actions are induced by points, like in any pointed variety. There we define semidirect products only for regular points, in the sense we explain below, provided the Split Short Five Lemma between such points holds, and we show that this is the case if the category is normal, as defined in [12]. Finally, we give an example of a category that is neither protomodular nor Mal’tsev where such generalized semidirect products exist.