-- Mathlib/Algebra/Algebra/NonUnitalSubalgebra.lean
theorem iSupLift_inclusion {i : ι} (x : K i) (h : K i ≤ T) :
    iSupLift K dir f hf T hT (inclusion h x) = f i x

Proof state:
R : Type u
A : Type v
B : Type w
inst✝⁷ : CommSemiring R
inst✝⁶ : NonUnitalNonAssocSemiring A
inst✝⁵ : Module R A
inst✝⁴ : NonUnitalNonAssocSemiring B
inst✝³ : Module R B
inst✝² : IsScalarTower R A A
inst✝¹ : SMulCommClass R A A
ι : Type u_1
inst✝ : Nonempty ι
K : ι → NonUnitalSubalgebra R A
dir : Directed (fun x1 x2 => x1 ≤ x2) K
f : (i : ι) → ↥(K i) →ₙₐ[R] B
hf : ∀ (i j : ι) (h : K i ≤ K j), f i = (f j).comp (inclusion h)
i : ι
x : ↥(K i)
h : K i ≤ iSup K
⊢ (iSupLift K dir f hf (iSup K) ⋯) ((inclusion h) x) = (f i) x

Tactic:
dsimp [iSupLift]

Result:
R : Type u
A : Type v
B : Type w
inst✝⁷ : CommSemiring R
inst✝⁶ : NonUnitalNonAssocSemiring A
inst✝⁵ : Module R A
inst✝⁴ : NonUnitalNonAssocSemiring B
inst✝³ : Module R B
inst✝² : IsScalarTower R A A
inst✝¹ : SMulCommClass R A A
ι : Type u_1
inst✝ : Nonempty ι
K : ι → NonUnitalSubalgebra R A
dir : Directed (fun x1 x2 => x1 ≤ x2) K
f : (i : ι) → ↥(K i) →ₙₐ[R] B
hf : ∀ (i j : ι) (h : K i ≤ K j), f i = (f j).comp (inclusion h)
i : ι
x : ↥(K i)
h : K i ≤ iSup K
⊢ Set.iUnionLift (fun i => ↑(K i)) (fun i x => (f i) x) ⋯ ↑(iSup K) ⋯ ((inclusion h) x) = (f i) x

Proof state:
case h
R : Type u
A : Type v
B : Type w
inst✝⁷ : CommSemiring R
inst✝⁶ : NonUnitalNonAssocSemiring A
inst✝⁵ : Module R A
inst✝⁴ : NonUnitalNonAssocSemiring B
inst✝³ : Module R B
inst✝² : IsScalarTower R A A
inst✝¹ : SMulCommClass R A A
ι : Type u_1
inst✝ : Nonempty ι
K : ι → NonUnitalSubalgebra R A
dir : Directed (fun x1 x2 => x1 ≤ x2) K
f : (i : ι) → ↥(K i) →ₙₐ[R] B
hf : ∀ (i j : ι) (h : K i ≤ K j), f i = (f j).comp (inclusion h)
i : ι
x : ↥(K i)
h : K i ≤ iSup K
⊢ ↑(K i) ⊆ ↑(iSup K)

Tactic:
exact h

Result:
no goals

Proof state:
R : Type u
A : Type v
B : Type w
inst✝⁷ : CommSemiring R
inst✝⁶ : NonUnitalNonAssocSemiring A
inst✝⁵ : Module R A
inst✝⁴ : NonUnitalNonAssocSemiring B
inst✝³ : Module R B
inst✝² : IsScalarTower R A A
inst✝¹ : SMulCommClass R A A
ι : Type u_1
inst✝ : Nonempty ι
K : ι → NonUnitalSubalgebra R A
dir : Directed (fun x1 x2 => x1 ≤ x2) K
f : (i : ι) → ↥(K i) →ₙₐ[R] B
hf : ∀ (i j : ι) (h : K i ≤ K j), f i = (f j).comp (inclusion h)
i : ι
x : ↥(K i)
h : K i ≤ iSup K
⊢ Set.iUnionLift (fun i => ↑(K i)) (fun i x => (f i) x) ⋯ ↑(iSup K) ⋯ ((inclusion h) x) = (f i) x

Tactic:
apply Set.iUnionLift_inclusion

Result:
case h
R : Type u
A : Type v
B : Type w
inst✝⁷ : CommSemiring R
inst✝⁶ : NonUnitalNonAssocSemiring A
inst✝⁵ : Module R A
inst✝⁴ : NonUnitalNonAssocSemiring B
inst✝³ : Module R B
inst✝² : IsScalarTower R A A
inst✝¹ : SMulCommClass R A A
ι : Type u_1
inst✝ : Nonempty ι
K : ι → NonUnitalSubalgebra R A
dir : Directed (fun x1 x2 => x1 ≤ x2) K
f : (i : ι) → ↥(K i) →ₙₐ[R] B
hf : ∀ (i j : ι) (h : K i ≤ K j), f i = (f j).comp (inclusion h)
i : ι
x : ↥(K i)
h : K i ≤ iSup K
⊢ ↑(K i) ⊆ ↑(iSup K)

Proof state:
R : Type u
A : Type v
B : Type w
inst✝⁷ : CommSemiring R
inst✝⁶ : NonUnitalNonAssocSemiring A
inst✝⁵ : Module R A
inst✝⁴ : NonUnitalNonAssocSemiring B
inst✝³ : Module R B
inst✝² : IsScalarTower R A A
inst✝¹ : SMulCommClass R A A
ι : Type u_1
inst✝ : Nonempty ι
K : ι → NonUnitalSubalgebra R A
dir : Directed (fun x1 x2 => x1 ≤ x2) K
f : (i : ι) → ↥(K i) →ₙₐ[R] B
hf : ∀ (i j : ι) (h : K i ≤ K j), f i = (f j).comp (inclusion h)
T : NonUnitalSubalgebra R A
hT : T = iSup K
i : ι
x : ↥(K i)
h : K i ≤ T
⊢ (iSupLift K dir f hf T hT) ((inclusion h) x) = (f i) x

Tactic:
subst T

Result:
R : Type u
A : Type v
B : Type w
inst✝⁷ : CommSemiring R
inst✝⁶ : NonUnitalNonAssocSemiring A
inst✝⁵ : Module R A
inst✝⁴ : NonUnitalNonAssocSemiring B
inst✝³ : Module R B
inst✝² : IsScalarTower R A A
inst✝¹ : SMulCommClass R A A
ι : Type u_1
inst✝ : Nonempty ι
K : ι → NonUnitalSubalgebra R A
dir : Directed (fun x1 x2 => x1 ≤ x2) K
f : (i : ι) → ↥(K i) →ₙₐ[R] B
hf : ∀ (i j : ι) (h : K i ≤ K j), f i = (f j).comp (inclusion h)
i : ι
x : ↥(K i)
h : K i ≤ iSup K
⊢ (iSupLift K dir f hf (iSup K) ⋯) ((inclusion h) x) = (f i) x