-- Mathlib/Algebra/Lie/Basic.lean
theorem coe_injective : @Function.Injective (L₁ →ₗ⁅R⁆ L₂) (L₁ → L₂) (↑)

Proof state:
case mk.mk.mk.mk.mk.mk
R : Type u
L₁ : Type v
L₂ : Type w
inst✝⁴ : CommRing R
inst✝³ : LieRing L₁
inst✝² : LieAlgebra R L₁
inst✝¹ : LieRing L₂
inst✝ : LieAlgebra R L₂
f : L₁ → L₂
map_add'✝¹ : ∀ (x y : L₁), f (x + y) = f x + f y
map_smul'✝¹ :
  ∀ (m : R) (x : L₁),
    { toFun := f, map_add' := map_add'✝¹ }.toFun (m • x) =
      (RingHom.id R) m • { toFun := f, map_add' := map_add'✝¹ }.toFun x
map_lie'✝¹ :
  ∀ {x y : L₁},
    { toFun := f, map_add' := map_add'✝¹, map_smul' := map_smul'✝¹ }.toFun ⁅x, y⁆ =
      ⁅{ toFun := f, map_add' := map_add'✝¹, map_smul' := map_smul'✝¹ }.toFun x,
        { toFun := f, map_add' := map_add'✝¹, map_smul' := map_smul'✝¹ }.toFun y⁆
g : L₁ → L₂
map_add'✝ : ∀ (x y : L₁), g (x + y) = g x + g y
map_smul'✝ :
  ∀ (m : R) (x : L₁),
    { toFun := g, map_add' := map_add'✝ }.toFun (m • x) =
      (RingHom.id R) m • { toFun := g, map_add' := map_add'✝ }.toFun x
map_lie'✝ :
  ∀ {x y : L₁},
    { toFun := g, map_add' := map_add'✝, map_smul' := map_smul'✝ }.toFun ⁅x, y⁆ =
      ⁅{ toFun := g, map_add' := map_add'✝, map_smul' := map_smul'✝ }.toFun x,
        { toFun := g, map_add' := map_add'✝, map_smul' := map_smul'✝ }.toFun y⁆
h :
  ⇑{ toFun := f, map_add' := map_add'✝¹, map_smul' := map_smul'✝¹, map_lie' := map_lie'✝¹ } =
    ⇑{ toFun := g, map_add' := map_add'✝, map_smul' := map_smul'✝, map_lie' := map_lie'✝ }
⊢ { toFun := f, map_add' := map_add'✝¹, map_smul' := map_smul'✝¹, map_lie' := map_lie'✝¹ } =
    { toFun := g, map_add' := map_add'✝, map_smul' := map_smul'✝, map_lie' := map_lie'✝ }

Tactic:
congr

Result:
no goals

Proof state:
R : Type u
L₁ : Type v
L₂ : Type w
inst✝⁴ : CommRing R
inst✝³ : LieRing L₁
inst✝² : LieAlgebra R L₁
inst✝¹ : LieRing L₂
inst✝ : LieAlgebra R L₂
⊢ Injective DFunLike.coe

Tactic:
rintro ⟨⟨⟨f, _⟩, _⟩, _⟩ ⟨⟨⟨g, _⟩, _⟩, _⟩ h

Result:
case mk.mk.mk.mk.mk.mk
R : Type u
L₁ : Type v
L₂ : Type w
inst✝⁴ : CommRing R
inst✝³ : LieRing L₁
inst✝² : LieAlgebra R L₁
inst✝¹ : LieRing L₂
inst✝ : LieAlgebra R L₂
f : L₁ → L₂
map_add'✝¹ : ∀ (x y : L₁), f (x + y) = f x + f y
map_smul'✝¹ :
  ∀ (m : R) (x : L₁),
    { toFun := f, map_add' := map_add'✝¹ }.toFun (m • x) =
      (RingHom.id R) m • { toFun := f, map_add' := map_add'✝¹ }.toFun x
map_lie'✝¹ :
  ∀ {x y : L₁},
    { toFun := f, map_add' := map_add'✝¹, map_smul' := map_smul'✝¹ }.toFun ⁅x, y⁆ =
      ⁅{ toFun := f, map_add' := map_add'✝¹, map_smul' := map_smul'✝¹ }.toFun x,
        { toFun := f, map_add' := map_add'✝¹, map_smul' := map_smul'✝¹ }.toFun y⁆
g : L₁ → L₂
map_add'✝ : ∀ (x y : L₁), g (x + y) = g x + g y
map_smul'✝ :
  ∀ (m : R) (x : L₁),
    { toFun := g, map_add' := map_add'✝ }.toFun (m • x) =
      (RingHom.id R) m • { toFun := g, map_add' := map_add'✝ }.toFun x
map_lie'✝ :
  ∀ {x y : L₁},
    { toFun := g, map_add' := map_add'✝, map_smul' := map_smul'✝ }.toFun ⁅x, y⁆ =
      ⁅{ toFun := g, map_add' := map_add'✝, map_smul' := map_smul'✝ }.toFun x,
        { toFun := g, map_add' := map_add'✝, map_smul' := map_smul'✝ }.toFun y⁆
h :
  ⇑{ toFun := f, map_add' := map_add'✝¹, map_smul' := map_smul'✝¹, map_lie' := map_lie'✝¹ } =
    ⇑{ toFun := g, map_add' := map_add'✝, map_smul' := map_smul'✝, map_lie' := map_lie'✝ }
⊢ { toFun := f, map_add' := map_add'✝¹, map_smul' := map_smul'✝¹, map_lie' := map_lie'✝¹ } =
    { toFun := g, map_add' := map_add'✝, map_smul' := map_smul'✝, map_lie' := map_lie'✝ }