# groupoid

A groupoid $G$ is a set together with a binary operation $\cdot:G\times G\longrightarrow G$. The groupoid (or “magma”) is closed under the operation.

There is also a separate, category-theoretic (http://planetmath.org/GroupoidCategoryTheoretic) definition of “groupoid.”

Title groupoid Groupoid 2013-03-22 12:16:03 2013-03-22 12:16:03 akrowne (2) akrowne (2) 11 akrowne (2) Definition msc 20N02 magma Semigroup Group LoopAndQuasigroup