Theorem: Unitization.lift_symm_apply
File: Mathlib/Algebra/Algebra/Unitization.lean

Proof steps:
state_before: S : Type u_1
R : Type u_2
A : Type u_3
inst✝¹² : CommSemiring S
inst✝¹¹ : CommSemiring R
inst✝¹⁰ : NonUnitalSemiring A
inst✝⁹ : Module R A
inst✝⁸ : SMulCommClass R A A
inst✝⁷ : IsScalarTower R A A
B : Type u_4
inst✝⁶ : Semiring B
inst✝⁵ : Algebra S B
inst✝⁴ : Algebra S R
inst✝³ : DistribMulAction S A
inst✝² : IsScalarTower S R A
C : Type u_5
inst✝¹ : Semiring C
inst✝ : Algebra R C
φ : A →ₙₐ[R] C
⊢ (fun φ => (↑φ).comp (inrNonUnitalAlgHom R A)) φ.toAlgHom = φ
state_after: case h
S : Type u_1
R : Type u_2
A : Type u_3
inst✝¹² : CommSemiring S
inst✝¹¹ : CommSemiring R
inst✝¹⁰ : NonUnitalSemiring A
inst✝⁹ : Module R A
inst✝⁸ : SMulCommClass R A A
inst✝⁷ : IsScalarTower R A A
B : Type u_4
inst✝⁶ : Semiring B
inst✝⁵ : Algebra S B
inst✝⁴ : Algebra S R
inst✝³ : DistribMulAction S A
inst✝² : IsScalarTower S R A
C : Type u_5
inst✝¹ : Semiring C
inst✝ : Algebra R C
φ : A →ₙₐ[R] C
x✝ : A
⊢ ((fun φ => (↑φ).comp (inrNonUnitalAlgHom R A)) φ.toAlgHom) x✝ = φ x✝
tactic: ext
state_before: case h
S : Type u_1
R : Type u_2
A : Type u_3
inst✝¹² : CommSemiring S
inst✝¹¹ : CommSemiring R
inst✝¹⁰ : NonUnitalSemiring A
inst✝⁹ : Module R A
inst✝⁸ : SMulCommClass R A A
inst✝⁷ : IsScalarTower R A A
B : Type u_4
inst✝⁶ : Semiring B
inst✝⁵ : Algebra S B
inst✝⁴ : Algebra S R
inst✝³ : DistribMulAction S A
inst✝² : IsScalarTower S R A
C : Type u_5
inst✝¹ : Semiring C
inst✝ : Algebra R C
φ : A →ₙₐ[R] C
x✝ : A
⊢ ((fun φ => (↑φ).comp (inrNonUnitalAlgHom R A)) φ.toAlgHom) x✝ = φ x✝
state_after: no goals
tactic: simp [NonUnitalAlgHomClass.toNonUnitalAlgHom]
state_before: S : Type u_1
R : Type u_2
A : Type u_3
inst✝¹² : CommSemiring S
inst✝¹¹ : CommSemiring R
inst✝¹⁰ : NonUnitalSemiring A
inst✝⁹ : Module R A
inst✝⁸ : SMulCommClass R A A
inst✝⁷ : IsScalarTower R A A
B : Type u_4
inst✝⁶ : Semiring B
inst✝⁵ : Algebra S B
inst✝⁴ : Algebra S R
inst✝³ : DistribMulAction S A
inst✝² : IsScalarTower S R A
C : Type u_5
inst✝¹ : Semiring C
inst✝ : Algebra R C
φ : Unitization R A →ₐ[R] C
⊢ ((fun φ => (↑φ).comp (inrNonUnitalAlgHom R A)) φ).toAlgHom = φ
state_after: case h.h
S : Type u_1
R : Type u_2
A : Type u_3
inst✝¹² : CommSemiring S
inst✝¹¹ : CommSemiring R
inst✝¹⁰ : NonUnitalSemiring A
inst✝⁹ : Module R A
inst✝⁸ : SMulCommClass R A A
inst✝⁷ : IsScalarTower R A A
B : Type u_4
inst✝⁶ : Semiring B
inst✝⁵ : Algebra S B
inst✝⁴ : Algebra S R
inst✝³ : DistribMulAction S A
inst✝² : IsScalarTower S R A
C : Type u_5
inst✝¹ : Semiring C
inst✝ : Algebra R C
φ : Unitization R A →ₐ[R] C
x✝ : A
⊢ ((↑((fun φ => (↑φ).comp (inrNonUnitalAlgHom R A)) φ).toAlgHom).comp (inrNonUnitalAlgHom R A)) x✝ =
    ((↑φ).comp (inrNonUnitalAlgHom R A)) x✝
tactic: ext
state_before: case h.h
S : Type u_1
R : Type u_2
A : Type u_3
inst✝¹² : CommSemiring S
inst✝¹¹ : CommSemiring R
inst✝¹⁰ : NonUnitalSemiring A
inst✝⁹ : Module R A
inst✝⁸ : SMulCommClass R A A
inst✝⁷ : IsScalarTower R A A
B : Type u_4
inst✝⁶ : Semiring B
inst✝⁵ : Algebra S B
inst✝⁴ : Algebra S R
inst✝³ : DistribMulAction S A
inst✝² : IsScalarTower S R A
C : Type u_5
inst✝¹ : Semiring C
inst✝ : Algebra R C
φ : Unitization R A →ₐ[R] C
x✝ : A
⊢ ((↑((fun φ => (↑φ).comp (inrNonUnitalAlgHom R A)) φ).toAlgHom).comp (inrNonUnitalAlgHom R A)) x✝ =
    ((↑φ).comp (inrNonUnitalAlgHom R A)) x✝
state_after: no goals
tactic: simp [NonUnitalAlgHomClass.toNonUnitalAlgHom]