English
An order isomorphism class provides a HeytingHomClass structure.
Русский
Изоморфизм порядка порождает структуру HeytingHomClass.
LaTeX
$$$ \text{OrderIsoClass } F α β \Rightarrow \text{HeytingHomClass } F α β$$$
Lean4
instance (priority := 100) toHeytingHomClass [HeytingAlgebra α] {_ : HeytingAlgebra β} [OrderIsoClass F α β] :
HeytingHomClass F α β :=
{ OrderIsoClass.toBoundedLatticeHomClass with
map_himp := fun f a b =>
eq_of_forall_le_iff fun c => by
simp only [← map_inv_le_iff, le_himp_iff]
rw [← OrderIsoClass.map_le_map_iff f]
simp }
-- See note [lower instance priority]