English
Inverse correspondence matches AddChar toMonoidHomEquiv.symm with MonoidHom.
Русский
Обратная корреспонденция сопоставляет AddChar toMonoidHomEquiv.symm с MonoidHom.
LaTeX
$$toMonoidHomEquiv.symm φ = f ⇔ φ = toMonoidHomEquiv f$$
Lean4
/-- Additive characters `A → M` are the same thing as additive homomorphisms from `A` to
`Additive M`. -/
def toAddMonoidHomEquiv : AddChar A M ≃ (A →+ Additive M)
where
toFun φ := φ.toAddMonoidHom
invFun
f :=
{ toFun := f.toFun
map_zero_eq_one' := f.map_zero'
map_add_eq_mul' := f.map_add' }