Bounded package:lattices

A join-semilattice with an identity element bottom for \/. Laws
x \/ bottom ≡ x
Corollary
x /\ bottom
≡⟨ identity ⟩
(x /\ bottom) \/ bottom
≡⟨ absorption ⟩
bottom
A meet-semilattice with an identity element top for /\. Laws
x /\ top ≡ x
Corollary
x \/ top
≡⟨ identity ⟩
(x \/ top) /\ top
≡⟨ absorption ⟩
top