English
Right cosets are in bijection with left cosets; there is a canonical isomorphism between α / s defined by left and right relations.
Русский
Правые косеты эквивалентны левым косетам; существует каноническое биекция между двумя представлениями α / s.
LaTeX
$$Right cosets ≃ Left cosets; equivalence α / (rightRel s) ≃ α / (leftRel s)$$
Lean4
@[to_additive]
theorem rightRel_eq : ⇑(rightRel s) = fun x y => y * x⁻¹ ∈ s :=
funext₂ <| by
simp only [eq_iff_iff]
apply rightRel_apply