English
Flipping the composition distributes: flip(r ∘r p) = flip p ∘r flip r.
Русский
Переворот композиции распределяется: flip(r ∘r p) = flip p ∘r flip r.
LaTeX
$$$\mathrm{flip}(\mathrm{Relation.Comp}(r,p)) = \mathrm{Relation.Comp}(\mathrm{flip}(p), \mathrm{flip}(r))$$$
Lean4
theorem flip_comp : flip (r ∘r p) = flip p ∘r flip r :=
by
funext c a
apply propext
constructor
· exact fun ⟨b, hab, hbc⟩ ↦ ⟨b, hbc, hab⟩
· exact fun ⟨b, hbc, hab⟩ ↦ ⟨b, hab, hbc⟩