# Unitary module

2010 Mathematics Subject Classification: Primary: 13C [MSN][ZBL]

A left (or right) module $M$ over a ring with identity $e$ such that multiplication by $e$ is the identity operator, i.e. the transformation $m\to em$ (respectively, $m\to me$ for right modules), $m\in M$, is the identity automorphism of the group $M$.