A groupoid (a category in which all morphisms are isomorphisms) defined from a topological space ; the objects are the points of , and the morphisms from an object to are the homotopy classes of paths starting at and ending at ; composition is the product of classes of paths. The group of automorphisms of an object is the same as the fundamental group .
A useful survey of the applications of fundamental groupoids can be found in [a1].
|[a1]||R. Brown, "From groups to groupoids: a brief survey" Bull. London Math. Soc. , 19 (1987) pp. 113–134|
Fundamental groupoid. Encyclopedia of Mathematics. URL: http://encyclopediaofmath.org/index.php?title=Fundamental_groupoid&oldid=12895