TITLE: Is it possible to express disjunction through conjunction and implication?
QUESTION [5 upvotes]: This question is about Boolean functions. Is it possible to express disjunction $x\lor y$ through conjunction $x\land y$ (or simply $xy$) and implication $x\to y$?

REPLY [9 votes]: Yes - in fact, disjunction is expressible via implication alone:
$$
x \lor y \equiv (x \to y) \to y
$$