Definition top_regular_element (H : complete_heyting_algebra) : regular_element H. Proof. use make_regular_element. - exact ⊤. - abstract (use make_is_regular_element ; rewrite cha_not_top ; rewrite cha_not_bot ; apply cha_le_refl). Defined.
Require Import UniMath.MoreFoundations.All. Require Import UniMath.Algebra.BinaryOperations. Require Import UniMath.OrderTheory.Lattice.Lattice. Require Import UniMath.OrderTheory.Lattice.Bounded. Require Import UniMath.OrderTheory.Lattice.Heyting. Require Import UniMath.OrderTheory.Lattice.CompleteHeyting. Require Import UniMath.OrderTheory.Lattice.DerivedLawsCompleteHeyting.