Definition:Alternative
From ProofWiki
Definition
Let $\circ$ be a binary operation.
Then $\circ$ is defined as being alternative on $S$ iff:
- $\forall T = \left\{{x, y}\right\} \subseteq S: \forall x, y, z \in T: \left({x \circ y}\right) \circ z = x \circ \left({y \circ z}\right)$
That is, $\circ$ is associative over any two elements of $S$.
For example, for any $x, y \in S$:
- $\left({x \circ y}\right) \circ x = x \circ \left({y \circ x}\right)$
- $\left({x \circ x}\right) \circ y = x \circ \left({x \circ y}\right)$
and so on.
Also see