Double groupoid
= Double groupoid
{wiki=Double_groupoid}
A double groupoid is a mathematical structure that generalizes the concept of a groupoid. To understand what a double groupoid is, it helps to first clarify what a groupoid is. \#\#\# Groupoid A **groupoid** consists of a set of objects and a set of morphisms (arrows) between these objects satisfying certain axioms. Specifically: - Each morphism has a source and target object.