- Heyting algebra. A Heyting algebra H is a bounded lattice in which the function fa: H → H, given by fa(x) = a ∧ x is the lower adjoint of a Galois connection, for every element a of H. The upper adjoint of fa is then denoted by ga, with ga(x) = a ⇒ x. Every Boolean algebra is a Heyting algebra.
- Hasse diagram. A Hasse diagram is a type of mathematical diagram used to represent a finite partially ordered set, in the form of a drawing of its transitive reduction.
Read more about this topic: Glossary Of Order Theory