 I shall adopt for the conception of multiplication the application of a relation, in such a way that, for example, \(\binary{l}\unary{w}\) shall denote whatever is a lover of a woman.…\(\binary{s}(\unary{m} \cunion \unary{w})\) will, then, denote whatever is a servant of anything of the class composed of men and women taken together. (DNLR [CP 3.68])