English
A Heyting homomorphism class F between Heyting algebras α and β induces a bounded lattice hom-class structure; in particular, top is preserved: f(⊤) = ⊤.
Русский
Класс гомоморфизмов Heyting между Heyting-алгебрами α и β индуцирует структуру класса гомоморфизмов ограниченной решетки; в частности, сохраняется верхний элемент: f(⊤) = ⊤.
LaTeX
$$$ \forall f,\ f(\top) = \top $$$
Lean4
instance (priority := 100) toBoundedLatticeHomClass [HeytingAlgebra α] {_ : HeytingAlgebra β} [HeytingHomClass F α β] :
BoundedLatticeHomClass F α β :=
{ ‹HeytingHomClass F α β› with map_top := fun f => by rw [← @himp_self α _ ⊥, ← himp_self, map_himp] }
-- See note [lower instance priority]