Groupoid

Infomrally a groupoid is the oidification of a group, or the categorification of an equivalence relation. Thus a groupoid is a category in which all morphisms are isomorphisms. #m/def/cat As such, it is a category augmented with an operation on morphisms $i n v$ (often written as $(-) - 1$ ) such that

𝑓 \circ i n v (𝑓) = i d = i n v (𝑓) \circ 𝑓

#state/develop | #SemBr | #lang/en