English
Left-composition with a fixed MulEquiv e is injective on MonoidHom M→*P.
Русский
Левая композиция с фиксированной MulEquiv e инъективна на множестве моноид-гомоморфизмов M →* P.
LaTeX
$$$$\text{Injective } (f \mapsto (e : M \to^* N).\,comp f). $$$$
Lean4
/-- `MulEquiv.symm` defines an equivalence between `α ≃* β` and `β ≃* α`. -/
@[to_additive (attr := simps!) /-- `AddEquiv.symm` defines an equivalence between `α ≃+ β` and `β ≃+ α` -/
]
def symmEquiv (P Q : Type*) [Mul P] [Mul Q] : (P ≃* Q) ≃ (Q ≃* P)
where
toFun := .symm
invFun := .symm