English
There is a natural bijection between the left cosets G/H and a transversal S, given by a left transversal isomorphism.
Русский
Существует естественная биекция между левавыми косетами G/H и поперечным набором S, заданная левым трансплантированием как изоморфизм.
LaTeX
$$$ leftQuotientEquiv \colon G/H \simeq S $$$
Lean4
/-- A left transversal is in bijection with left cosets. -/
@[to_additive /-- A left transversal is in bijection with left cosets. -/
]
noncomputable def leftQuotientEquiv (hS : IsComplement S H) : G ⧸ H ≃ S :=
(Equiv.ofBijective _ (isComplement_subgroup_right_iff_bijective.mp hS)).symm