Definition:Entropic Operation

Definition
Let $\circ$ be an operation on a set $S$ such that:


 * $\forall a, b, c, d \in S: \left({a \circ b}\right) \circ \left({c \circ d}\right) = \left({a \circ c}\right) \circ \left({b \circ d}\right)$

Then $\circ$ is entropic.