English
There is a natural equivalence between the space of characters on a normed algebra and the space of algebra homomorphisms from the algebra to the base field.
Русский
Существует естественное эквивалентное соотношение между пространством характеров и алгебраических гомоморфизмов в базовое поле.
LaTeX
$$characterSpace 𝕜 A ≃ (A →ₐ[𝕜] 𝕜)$$
Lean4
/-- The equivalence between characters and algebra homomorphisms into the base field. -/
def equivAlgHom : characterSpace 𝕜 A ≃ (A →ₐ[𝕜] 𝕜)
where
toFun := toAlgHom
invFun
f :=
{ val := f.toContinuousLinearMap
property := by rw [eq_set_map_one_map_mul]; exact ⟨map_one f, map_mul f⟩ }