6533b870fe1ef96bd12cfd81

RESEARCH PRODUCT

Butterflies in a Semi-Abelian Context

Enrico VitaleSandra MantovaniGiuseppe MetereO. Abbad

subject

Discrete mathematicsPure mathematicsButterflyFunctorInternal groupoidWeak equivalenceGeneral MathematicsSemi-abelian categoryFunctor categoryContext (language use)Mathematics - Category TheoryBicategory of fractionBicategoryMathematics::Algebraic TopologyWeak equivalence18D05 18B40 18E10 18A40Surjective functionMorphismMathematics::Category TheoryFOS: MathematicsCategory Theory (math.CT)Abelian groupMathematics

description

It is known that monoidal functors between internal groupoids in the category Grp of groups constitute the bicategory of fractions of the 2-category Grpd(Grp) of internal groupoids, internal functors and internal natural transformations in Grp, with respect to weak equivalences (that is, internal functors which are internally fully faithful and essentially surjective on objects). Monoidal functors can be equivalently described by a kind of weak morphisms introduced by B. Noohi under the name of butterflies. In order to internalize monoidal functors in a wide context, we introduce the notion of internal butterflies between internal crossed modules in a semi-abelian category C, and we show that they are morphisms of a bicategory B(C). Our main result states that, when in C the notions of Huq commutator and Smith commutator coincide, then the bicategory B(C) of internal butterflies is the bicategory of fractions of Grpd(C) with respect to weak equivalences. (C) 2013 Elsevier Inc. All rights reserved.

yearjournalcountryeditionlanguage
2011-04-21
http://arxiv.org/abs/1104.4275