In this paper we use Quillen’s model structure given by Dwyer-Kan for the category of simplicial groupoids (with discrete object of objects) to describe in this category, in the simplicial language, the fundamental homotopy theoretical constructions of path and cylinder objects. We then characterize the associated left and right homotopy relations in terms of simplicial identities and give a si...

In a series of papers, we have shown that from the representation theory of a compact groupoid one can reconstruct the groupoid using the procedure similar to the Tannaka-Krein duality for compact groups. In this part we study continuous representations of compact groupoids. We show that irreducible representationshave finite dimensional fibres. We prove the Schur’s lemma, Gelfand-Raikov theore...

Decompositions of the complete graph with n vertices Kn into edge disjoint cycles of length m whose union is Kn are commonly called w-cycle systems. Any m-cycle system gives rise to a groupoid defined on the vertex set of Kn via a well known construction. Here, it is shown that the groupoids arising from all m-cycle systems are precisely the finite members of a variety (of groupoids) for m = 3 ...

The main purpose of this paper is to develop new tools for the investigation of C-algebras which have been constructed from shift spaces in a series of papers by K. Matsumoto and T. Carlsen, cf. [Ma1]-[Ma5], [C], [CM]. The main results about the structure of these algebras which we obtain here give necessary and sufficient conditions for the algebras to be simple, and show that they all contain...

In this paper, we introduce transposition regularity into AG-groupoids, and a variety of regular AG-groupoids (L1/R1/LR, L2/R2/L3/R3-groupoids) are obtained. Their properties structures discussed by their decomposition theorems: (1) L1/R1-transposition equivalent to each other, they can be decomposed the union disjoint Abelian subgroups; (2) LR-transposition an example is given illustrate that ...

This paper is concerned with the algebraic structure of groupoids and crossed modules of groupoids. We describe the group structure of the automorphism group of a finite connected groupoid C as a quotient of a semidirect product. We pay particular attention to the conjugation automorphisms of C, and use these to define a new notion of groupoid action. We then show that the automorphism group of...

In this note a functorial approach to the integration problem of an LAgroupoid to a double Lie groupoid is discussed. To do that, we study the notions of fibered products in the categories of Lie groupoids and Lie algebroids, giving necessary and sufficient conditions for the existence of such. In particular, it turns out, that the fibered product of Lie algebroids along integrable morphisms is...