LocalFieldTheory.additiveEquivOfMulEquiv
Transport a multiplicative equivalence to an additive equivalence.
Source context 3 commands
Surrounding namespaces, section variables, and local commands at this declaration.
namespace LocalFieldTheory
noncomputable section
universe uLean source · full declaration
def additiveEquivOfMulEquiv {A B : Type u} [Group A] [Group B] (e : A ≃* B) :
Additive A ≃+ Additive B where
toFun := fun a => Additive.ofMul (e (Additive.toMul a))
invFun := fun b => Additive.ofMul (e.symm (Additive.toMul b))
left_inv := by
intro a
simp
right_inv := by
intro b
simp
map_add' := by
intro a b
ext
exact e.map_mul _ _