In
category theory, a branch of mathematics, a globular set is a higher-dimensional generalization of a
directed graph
In mathematics, and more specifically in graph theory, a directed graph (or digraph) is a graph that is made up of a set of vertices connected by directed edges, often called arcs.
Definition
In formal terms, a directed graph is an ordered pai ...
. Precisely, it is a sequence of sets
equipped with pairs of functions
such that
*
*
(Equivalently, it is a
presheaf on the category of βglobesβ.) The letters "''s''", "''t''" stand for "source" and "target" and one imagines
consists of directed edges at level ''n''.
A variant of the notion was used by
Grothendieck to introduce the notion of an
β-groupoid
In category theory, a branch of mathematics, an β-groupoid is an abstract homotopical model for topological spaces. One model uses Kan complexes which are fibrant objects in the category of simplicial sets (with the standard model structure). I ...
. Extending Grothendieck's work,
gave a definition of a
weak β-category
In mathematics, more specifically category theory, a quasi-category (also called quasicategory, weak Kan complex, inner Kan complex, infinity category, β-category, Boardman complex, quategory) is a generalization of the notion of a category. Th ...
in terms of globular sets.
References
Further reading
*Dimitri Ara. On the homotopy theory of Grothendieck β -groupoids. ''J. Pure Appl. Algebra'', 217(7):1237β1278, 2013, arXiv:1206.2941 .
External links
*https://ncatlab.org/nlab/show/globular+set
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Category theory