"`baz` is associative and `quux` is an identity element." (Though normally the latter would be more like "`quux` is a noop", "`quux` is an empty set", or whate

"`baz` is associative and `quux` is an identity element." (Though normally the latter would be more like "`quux` is a noop", "`quux` is an empty set", or whatever domain-specific term you need, and the associativity claim would be a brief parenthetical inside meaningful documentation.)