English
If e.source = univ, then the symmetric surjective property holds: e.symm is surjective.
Русский
Если источник эквивалентности равен универсу, то симметричная карта сюръективна.
LaTeX
$$$Eq e.source\\mathrm{ = univ} \\Rightarrow \\text{Surjective}(e^{\\mathrm{symm}})$$$
Lean4
@[simp, mfld_simps]
theorem trans_transPartialEquiv (e : α ≃ β) (e' : β ≃ γ) (f'' : PartialEquiv γ δ) :
(e.trans e').transPartialEquiv f'' = e.transPartialEquiv (e'.transPartialEquiv f'') := by
simp only [transPartialEquiv_eq_trans, PartialEquiv.trans_assoc, trans_toPartialEquiv]