Levi categories and graphs of groups
Theory and applications of categories, Tome 32 (2017), pp. 780-802
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We define a Levi category to be a weakly orthogonal category equipped with a suitable length functor and prove two main theorems about them. First, skeletal cancellative Levi categories are precisely the categorical versions of graphs of groups with a given orientation. Second, the universal groupoid of a skeletal cancellative Levi category is the fundamental groupoid of the corresponding graph of groups. These two results can be viewed as a co-ordinate-free refinement of a classical theorem of Philip Higgins.
Publié le :
Classification :
18B40, 20E06
Keywords: Graphs of groups, self-similar groupoid actions, cancellative categories
Keywords: Graphs of groups, self-similar groupoid actions, cancellative categories
@article{TAC_2017_32_a22,
author = {Mark V. Lawson and Alistair R. Wallis},
title = {Levi categories and graphs of groups},
journal = {Theory and applications of categories},
pages = {780--802},
publisher = {mathdoc},
volume = {32},
year = {2017},
language = {en},
url = {http://geodesic.mathdoc.fr/item/TAC_2017_32_a22/}
}
Mark V. Lawson; Alistair R. Wallis. Levi categories and graphs of groups. Theory and applications of categories, Tome 32 (2017), pp. 780-802. http://geodesic.mathdoc.fr/item/TAC_2017_32_a22/