Theorem: StarAlgHom.mk_coe
File: Mathlib/Algebra/Star/StarAlgHom.lean

Proof steps:
state_before: F : Type u_1
R : Type u_2
A : Type u_3
B : Type u_4
C : Type u_5
D : Type u_6
inst✝¹² : CommSemiring R
inst✝¹¹ : Semiring A
inst✝¹⁰ : Algebra R A
inst✝⁹ : Star A
inst✝⁸ : Semiring B
inst✝⁷ : Algebra R B
inst✝⁶ : Star B
inst✝⁵ : Semiring C
inst✝⁴ : Algebra R C
inst✝³ : Star C
inst✝² : Semiring D
inst✝¹ : Algebra R D
inst✝ : Star D
f : A →⋆ₐ[R] B
h₁ : f 1 = 1
h₂ :
  ∀ (x y : A),
    { toFun := ⇑f, map_one' := h₁ }.toFun (x * y) =
      { toFun := ⇑f, map_one' := h₁ }.toFun x * { toFun := ⇑f, map_one' := h₁ }.toFun y
h₃ : (↑{ toFun := ⇑f, map_one' := h₁, map_mul' := h₂ }).toFun 0 = 0
h₄ :
  ∀ (x y : A),
    (↑{ toFun := ⇑f, map_one' := h₁, map_mul' := h₂ }).toFun (x + y) =
      (↑{ toFun := ⇑f, map_one' := h₁, map_mul' := h₂ }).toFun x +
        (↑{ toFun := ⇑f, map_one' := h₁, map_mul' := h₂ }).toFun y
h₅ :
  ∀ (r : R),
    (↑↑{ toFun := ⇑f, map_one' := h₁, map_mul' := h₂, map_zero' := h₃, map_add' := h₄ }).toFun ((algebraMap R A) r) =
      (algebraMap R B) r
h₆ :
  ∀ (x : A),
    (↑↑{ toFun := ⇑f, map_one' := h₁, map_mul' := h₂, map_zero' := h₃, map_add' := h₄,
                  commutes' := h₅ }.toRingHom).toFun
        (star x) =
      star
        ((↑↑{ toFun := ⇑f, map_one' := h₁, map_mul' := h₂, map_zero' := h₃, map_add' := h₄,
                    commutes' := h₅ }.toRingHom).toFun
          x)
⊢ { toFun := ⇑f, map_one' := h₁, map_mul' := h₂, map_zero' := h₃, map_add' := h₄, commutes' := h₅, map_star' := h₆ } = f
state_after: case h
F : Type u_1
R : Type u_2
A : Type u_3
B : Type u_4
C : Type u_5
D : Type u_6
inst✝¹² : CommSemiring R
inst✝¹¹ : Semiring A
inst✝¹⁰ : Algebra R A
inst✝⁹ : Star A
inst✝⁸ : Semiring B
inst✝⁷ : Algebra R B
inst✝⁶ : Star B
inst✝⁵ : Semiring C
inst✝⁴ : Algebra R C
inst✝³ : Star C
inst✝² : Semiring D
inst✝¹ : Algebra R D
inst✝ : Star D
f : A →⋆ₐ[R] B
h₁ : f 1 = 1
h₂ :
  ∀ (x y : A),
    { toFun := ⇑f, map_one' := h₁ }.toFun (x * y) =
      { toFun := ⇑f, map_one' := h₁ }.toFun x * { toFun := ⇑f, map_one' := h₁ }.toFun y
h₃ : (↑{ toFun := ⇑f, map_one' := h₁, map_mul' := h₂ }).toFun 0 = 0
h₄ :
  ∀ (x y : A),
    (↑{ toFun := ⇑f, map_one' := h₁, map_mul' := h₂ }).toFun (x + y) =
      (↑{ toFun := ⇑f, map_one' := h₁, map_mul' := h₂ }).toFun x +
        (↑{ toFun := ⇑f, map_one' := h₁, map_mul' := h₂ }).toFun y
h₅ :
  ∀ (r : R),
    (↑↑{ toFun := ⇑f, map_one' := h₁, map_mul' := h₂, map_zero' := h₃, map_add' := h₄ }).toFun ((algebraMap R A) r) =
      (algebraMap R B) r
h₆ :
  ∀ (x : A),
    (↑↑{ toFun := ⇑f, map_one' := h₁, map_mul' := h₂, map_zero' := h₃, map_add' := h₄,
                  commutes' := h₅ }.toRingHom).toFun
        (star x) =
      star
        ((↑↑{ toFun := ⇑f, map_one' := h₁, map_mul' := h₂, map_zero' := h₃, map_add' := h₄,
                    commutes' := h₅ }.toRingHom).toFun
          x)
x✝ : A
⊢ { toFun := ⇑f, map_one' := h₁, map_mul' := h₂, map_zero' := h₃, map_add' := h₄, commutes' := h₅, map_star' := h₆ }
      x✝ =
    f x✝
tactic: ext
state_before: case h
F : Type u_1
R : Type u_2
A : Type u_3
B : Type u_4
C : Type u_5
D : Type u_6
inst✝¹² : CommSemiring R
inst✝¹¹ : Semiring A
inst✝¹⁰ : Algebra R A
inst✝⁹ : Star A
inst✝⁸ : Semiring B
inst✝⁷ : Algebra R B
inst✝⁶ : Star B
inst✝⁵ : Semiring C
inst✝⁴ : Algebra R C
inst✝³ : Star C
inst✝² : Semiring D
inst✝¹ : Algebra R D
inst✝ : Star D
f : A →⋆ₐ[R] B
h₁ : f 1 = 1
h₂ :
  ∀ (x y : A),
    { toFun := ⇑f, map_one' := h₁ }.toFun (x * y) =
      { toFun := ⇑f, map_one' := h₁ }.toFun x * { toFun := ⇑f, map_one' := h₁ }.toFun y
h₃ : (↑{ toFun := ⇑f, map_one' := h₁, map_mul' := h₂ }).toFun 0 = 0
h₄ :
  ∀ (x y : A),
    (↑{ toFun := ⇑f, map_one' := h₁, map_mul' := h₂ }).toFun (x + y) =
      (↑{ toFun := ⇑f, map_one' := h₁, map_mul' := h₂ }).toFun x +
        (↑{ toFun := ⇑f, map_one' := h₁, map_mul' := h₂ }).toFun y
h₅ :
  ∀ (r : R),
    (↑↑{ toFun := ⇑f, map_one' := h₁, map_mul' := h₂, map_zero' := h₃, map_add' := h₄ }).toFun ((algebraMap R A) r) =
      (algebraMap R B) r
h₆ :
  ∀ (x : A),
    (↑↑{ toFun := ⇑f, map_one' := h₁, map_mul' := h₂, map_zero' := h₃, map_add' := h₄,
                  commutes' := h₅ }.toRingHom).toFun
        (star x) =
      star
        ((↑↑{ toFun := ⇑f, map_one' := h₁, map_mul' := h₂, map_zero' := h₃, map_add' := h₄,
                    commutes' := h₅ }.toRingHom).toFun
          x)
x✝ : A
⊢ { toFun := ⇑f, map_one' := h₁, map_mul' := h₂, map_zero' := h₃, map_add' := h₄, commutes' := h₅, map_star' := h₆ }
      x✝ =
    f x✝
state_after: no goals
tactic: rfl