English
Composition of equivalences respects optionCongr: optionCongr (e1.trans e2) equals (optionCongr e1).trans (optionCongr e2).
Русский
Суммирование эквивалентностей в отношении Option сохраняется: optionCongr (e1.trans e2) = (optionCongr e1).trans (optionCongr e2).
LaTeX
$$$\\text{optionCongr}(e_1\\,\\text{trans } e_2) = (\\text{optionCongr } e_1).\\text{trans } (\\text{optionCongr } e_2).$$$
Lean4
@[simp]
theorem optionCongr_trans (e₁ : α ≃ β) (e₂ : β ≃ γ) :
optionCongr (e₁.trans e₂) = (optionCongr e₁).trans (optionCongr e₂) :=
by
ext x : 1
symm
apply Option.map_map