Theorems · Theorem · ring theory

MonoidAlgebra.algHom_ext

∀ {R : Type u_1} {A : Type u_4} {B : Type u_5} {M : Type u_7} [inst : CommSemiring R] [inst_1 : Semiring A]
  [inst_2 : Semiring B] [inst_3 : Algebra R A] [inst_4 : Algebra R B] [inst_5 : Monoid M]
  ⦃φ₁ φ₂ : MonoidAlgebra A M →ₐ[R] B⦄,
  (∀ (m : M), φ₁ (MonoidAlgebra.single m 1) = φ₂ (MonoidAlgebra.single m 1)) →
    φ₁.comp MonoidAlgebra.singleOneAlgHom = φ₂.comp MonoidAlgebra.singleOneAlgHom → φ₁ = φ₂

A R-algebra homomorphism from A[M] is uniquely defined by its values on the functions single m 1 and single 1 a. See note [partially-applied ext lemmas]. Note that the first assumption isn't written as an equality of MonoidHoms because of doesn't additivise.

Defined in

Mathlib.Algebra.MonoidAlgebra.Basic

Cited by

7 results in Mathlib

Foundations

Depth 87 from the axioms · uses propext, Classical.choice, Quot.sound

Assumes

CommSemiringSemiringSemiringAlgebraAlgebraMonoid