Search results for "Internal groupoid"

showing 7 items of 7 documents

The snail lemma for internal groupoids

2019

Abstract We establish a generalized form both of the Gabriel-Zisman exact sequence associated with a pointed functor between pointed groupoids, and of the Brown exact sequence associated with a fibration of pointed groupoids. Our generalization consists in replacing pointed groupoids with groupoids internal to a pointed regular category with reflexive coequalizers.

Pure mathematicsExact sequenceLemma (mathematics)Internal groupoid Snail lemma Fibration Snake lemmaAlgebra and Number TheoryFunctorMathematics::Operator Algebras010102 general mathematicsFibrationMathematics - Category Theory01 natural sciences18B40 18D35 18G50Settore MAT/02 - AlgebraMathematics::K-Theory and HomologyMathematics::Category Theory0103 physical sciencesFOS: MathematicsCategory Theory (math.CT)Regular category010307 mathematical physics0101 mathematicsMathematics::Symplectic GeometryMathematics
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External derivations of internal groupoids

2008

If His a G-crossed module, the set of derivations of Gin H is a monoid under the Whitehead product of derivations. We interpret the Whitehead product using the correspondence between crossed modules and internal groupoids in the category of groups. Working in the general context of internal groupoids in a finitely complete category, we relate derivations to holomorphisms, translations, affine transformations, and to the embedding category of a groupoid. (C) 2007 Elsevier B.V. All rights reserved.

Higher-dimensional algebraAlgebra and Number TheoryComplete categoryCategory of groupsContext (language use)derivations crossed modules internal groupoids holomorphismsAlgebraSettore MAT/02 - AlgebraMathematics::K-Theory and HomologyMathematics::Category TheoryMonoid (category theory)EmbeddingAffine transformationMathematics::Symplectic GeometryMathematicsWhitehead productJournal of Pure and Applied Algebra
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Bipullbacks of fractions and the snail lemma

2017

Abstract We establish conditions giving the existence of bipullbacks in bicategories of fractions. We apply our results to construct a π 0 - π 1 exact sequence associated with a fractor between groupoids internal to a pointed exact category.

Pure mathematicsLemma (mathematics)Exact sequenceInternal groupoidAlgebra and Number Theory010102 general mathematicsMathematics - Category TheoryBicategory of fraction18B40 18D05 18E35 18G5001 natural sciencesMathematics::Algebraic TopologySettore MAT/02 - AlgebraExact categoryMathematics::K-Theory and HomologyMathematics::Category Theory0103 physical sciencesFOS: MathematicsBipullbackSnail lemmaCategory Theory (math.CT)010307 mathematical physics0101 mathematicsMathematics
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On Fibrations Between Internal Groupoids and Their Normalizations

2018

We characterize fibrations and $$*$$ -fibrations in the 2-category of internal groupoids in terms of the comparison functor from certain pullbacks to the corresponding strong homotopy pullbacks. As an application, we deduce the internal version of the Brown exact sequence for $$*$$ -fibrations from the internal version of the Gabriel–Zisman exact sequence. We also analyse fibrations and $$*$$ -fibrations in the category of arrows and study when the normalization functor preserves and reflects them. This analysis allows us to give a characterization of protomodular categories using strong homotopy kernels and a generalization of the Snake Lemma.

Normalization (statistics)Pure mathematicsInternal groupoid Fibration Strong h-pullback Protomodular categoryGeneral Computer ScienceFibrationSnake lemmaStrong h-pullbackMathematics::Algebraic Topology01 natural sciencesTheoretical Computer ScienceMathematics::Algebraic GeometryMathematics::K-Theory and HomologyMathematics::Category Theory0103 physical sciences0101 mathematicsMathematics::Symplectic GeometryMathematicsExact sequenceInternal groupoidAlgebra and Number TheoryFunctorHomotopy010102 general mathematicsFibrationInternal versionSettore MAT/02 - AlgebraProtomodular categoryTheory of computation010307 mathematical physicsApplied Categorical Structures
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Distributors and the comprehensive factorization system for internal groupoids

2017

In this note we prove that distributors between groupoids in a Barr-exact category epsilon form the bicategory of relations relative to the comprehensive factorization system in Gpd(epsilon). The case epsilon = Set is of special interest.

Settore MAT/02 - AlgebraMathematics::Category Theoryinternal groupoidprofunctorFOS: MathematicsMathematics - Category TheoryCategory Theory (math.CT)factorization systemdistributor18A32 20L05
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Butterflies in a Semi-Abelian Context

2011

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 th…

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
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Braided and symmetric internal groupoids

2011

Braided and symmetric internal groupoids in semi-abelian categories are discussed.

Settore MAT/02 - AlgebraInternal groupoids braided symmetric
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