Ternary operation

Summary

A ternary operation on a set $A$ is a finitary operation of arity $3$, a function from $A^3$ to $A$. Ternary operations appear naturally in universal algebra. Examples are the operation $x y^{-1} z$ of a group, which turns a group into a heap, and the ternary discriminator. Many conditions on varieties are stated with ternary terms, such as a Mal'cev term or a majority term.