Theorem: LinearMap.continuous_on_pi
File: Mathlib/Topology/Algebra/Module/Basic.lean

tactic: cases nonempty_fintype ι
state_before: ι : Type u_1
R : Type u_2
M : Type u_3
inst✝⁷ : Finite ι
inst✝⁶ : Semiring R
inst✝⁵ : TopologicalSpace R
inst✝⁴ : AddCommMonoid M
inst✝³ : Module R M
inst✝² : TopologicalSpace M
inst✝¹ : ContinuousAdd M
inst✝ : ContinuousSMul R M
f : (ι → R) →ₗ[R] M
⊢ Continuous ↑f

tactic: classical
  have : (f : (ι → R) → M) = fun x => ∑ i : ι, x i • f fun j => if i = j then 1 else 0 := by
    ext x
    exact f.pi_apply_eq_sum_univ x
  rw [this]
  refine continuous_finset_sum _ fun i _ => ?_
  exact (continuous_apply i).smul continuous_const
state_before: case intro
ι : Type u_1
R : Type u_2
M : Type u_3
inst✝⁷ : Finite ι
inst✝⁶ : Semiring R
inst✝⁵ : TopologicalSpace R
inst✝⁴ : AddCommMonoid M
inst✝³ : Module R M
inst✝² : TopologicalSpace M
inst✝¹ : ContinuousAdd M
inst✝ : ContinuousSMul R M
f : (ι → R) →ₗ[R] M
val✝ : Fintype ι
⊢ Continuous ↑f

tactic: have : (f : (ι → R) → M) = fun x => ∑ i : ι, x i • f fun j => if i = j then 1 else 0 := by
  ext x
  exact f.pi_apply_eq_sum_univ x
state_before: case intro
ι : Type u_1
R : Type u_2
M : Type u_3
inst✝⁷ : Finite ι
inst✝⁶ : Semiring R
inst✝⁵ : TopologicalSpace R
inst✝⁴ : AddCommMonoid M
inst✝³ : Module R M
inst✝² : TopologicalSpace M
inst✝¹ : ContinuousAdd M
inst✝ : ContinuousSMul R M
f : (ι → R) →ₗ[R] M
val✝ : Fintype ι
⊢ Continuous ↑f

tactic: rw [this]
state_before: case intro
ι : Type u_1
R : Type u_2
M : Type u_3
inst✝⁷ : Finite ι
inst✝⁶ : Semiring R
inst✝⁵ : TopologicalSpace R
inst✝⁴ : AddCommMonoid M
inst✝³ : Module R M
inst✝² : TopologicalSpace M
inst✝¹ : ContinuousAdd M
inst✝ : ContinuousSMul R M
f : (ι → R) →ₗ[R] M
val✝ : Fintype ι
this : ↑f = fun x => ∑ i : ι, x i • ↑f fun j => if i = j then 1 else 0
⊢ Continuous ↑f

tactic: refine continuous_finset_sum _ fun i _ => ?_
state_before: case intro
ι : Type u_1
R : Type u_2
M : Type u_3
inst✝⁷ : Finite ι
inst✝⁶ : Semiring R
inst✝⁵ : TopologicalSpace R
inst✝⁴ : AddCommMonoid M
inst✝³ : Module R M
inst✝² : TopologicalSpace M
inst✝¹ : ContinuousAdd M
inst✝ : ContinuousSMul R M
f : (ι → R) →ₗ[R] M
val✝ : Fintype ι
this : ↑f = fun x => ∑ i : ι, x i • ↑f fun j => if i = j then 1 else 0
⊢ Continuous fun x => ∑ i : ι, x i • ↑f fun j => if i = j then 1 else 0

tactic: exact (continuous_apply i).smul continuous_const
state_before: case intro
ι : Type u_1
R : Type u_2
M : Type u_3
inst✝⁷ : Finite ι
inst✝⁶ : Semiring R
inst✝⁵ : TopologicalSpace R
inst✝⁴ : AddCommMonoid M
inst✝³ : Module R M
inst✝² : TopologicalSpace M
inst✝¹ : ContinuousAdd M
inst✝ : ContinuousSMul R M
f : (ι → R) →ₗ[R] M
val✝ : Fintype ι
this : ↑f = fun x => ∑ i : ι, x i • ↑f fun j => if i = j then 1 else 0
i : ι
x✝ : i ∈ Finset.univ
⊢ Continuous fun x => x i • ↑f fun j => if i = j then 1 else 0

tactic: ext x
state_before: ι : Type u_1
R : Type u_2
M : Type u_3
inst✝⁷ : Finite ι
inst✝⁶ : Semiring R
inst✝⁵ : TopologicalSpace R
inst✝⁴ : AddCommMonoid M
inst✝³ : Module R M
inst✝² : TopologicalSpace M
inst✝¹ : ContinuousAdd M
inst✝ : ContinuousSMul R M
f : (ι → R) →ₗ[R] M
val✝ : Fintype ι
⊢ ↑f = fun x => ∑ i : ι, x i • ↑f fun j => if i = j then 1 else 0

tactic: exact f.pi_apply_eq_sum_univ x
state_before: case h
ι : Type u_1
R : Type u_2
M : Type u_3
inst✝⁷ : Finite ι
inst✝⁶ : Semiring R
inst✝⁵ : TopologicalSpace R
inst✝⁴ : AddCommMonoid M
inst✝³ : Module R M
inst✝² : TopologicalSpace M
inst✝¹ : ContinuousAdd M
inst✝ : ContinuousSMul R M
f : (ι → R) →ₗ[R] M
val✝ : Fintype ι
x : ι → R
⊢ ↑f x = ∑ i : ι, x i • ↑f fun j => if i = j then 1 else 0