\begin{definition}[Definition:Antihomomorphism]
Let $\phi: \struct {S, \circ} \to \struct {T, *}$ be a mapping from one algebraic structure $\struct {S, \circ}$ to another $\struct {T, *}$.
Then $\phi$ is an '''antihomomorphism''' {{iff}}:
:$\forall x, y \in S: \map \phi {x \circ y} = \map \phi y * \map \phi x$
For structures with more than one operation, $\phi$ may be '''antihomomorphic''' for a subset of those operations.
\end{definition}