-- Mathlib/Analysis/Convex/GaugeRescale.lean
theorem continuous_gaugeRescale {s t : Set E} (hs : Convex ℝ s) (hs₀ : s ∈ 𝓝 0)
    (ht : Convex ℝ t) (ht₀ : t ∈ 𝓝 0) (htb : IsVonNBounded ℝ t) :
    Continuous (gaugeRescale s t)

Proof state:
case inr
E : Type u_1
inst✝⁵ : AddCommGroup E
inst✝⁴ : Module ℝ E
inst✝³ : TopologicalSpace E
inst✝² : IsTopologicalAddGroup E
inst✝¹ : ContinuousSMul ℝ E
inst✝ : T1Space E
s t : Set E
hs : Convex ℝ s
hs₀ : s ∈ 𝓝 0
ht : Convex ℝ t
ht₀ : t ∈ 𝓝 0
htb : IsVonNBounded ℝ t
hta : Absorbent ℝ t
x : E
hx : x ≠ 0
⊢ ContinuousAt (gaugeRescale s t) x

Tactic:
exact ((continuousAt_gauge hs hs₀).div (continuousAt_gauge ht ht₀)
  ((gauge_pos hta htb).2 hx).ne').smul continuousAt_id

Result:
no goals

Proof state:
E : Type u_1
inst✝⁵ : AddCommGroup E
inst✝⁴ : Module ℝ E
inst✝³ : TopologicalSpace E
inst✝² : IsTopologicalAddGroup E
inst✝¹ : ContinuousSMul ℝ E
inst✝ : T1Space E
s t : Set E
hs : Convex ℝ s
hs₀ : s ∈ 𝓝 0
ht : Convex ℝ t
ht₀ : t ∈ 𝓝 0
htb : IsVonNBounded ℝ t
⊢ Continuous (gaugeRescale s t)

Tactic:
have hta : Absorbent ℝ t := absorbent_nhds_zero ht₀

Result:
E : Type u_1
inst✝⁵ : AddCommGroup E
inst✝⁴ : Module ℝ E
inst✝³ : TopologicalSpace E
inst✝² : IsTopologicalAddGroup E
inst✝¹ : ContinuousSMul ℝ E
inst✝ : T1Space E
s t : Set E
hs : Convex ℝ s
hs₀ : s ∈ 𝓝 0
ht : Convex ℝ t
ht₀ : t ∈ 𝓝 0
htb : IsVonNBounded ℝ t
hta : Absorbent ℝ t
⊢ Continuous (gaugeRescale s t)

Proof state:
case inl
E : Type u_1
inst✝⁵ : AddCommGroup E
inst✝⁴ : Module ℝ E
inst✝³ : TopologicalSpace E
inst✝² : IsTopologicalAddGroup E
inst✝¹ : ContinuousSMul ℝ E
inst✝ : T1Space E
s t : Set E
hs : Convex ℝ s
hs₀ : s ∈ 𝓝 0
ht : Convex ℝ t
ht₀ : t ∈ 𝓝 0
htb : IsVonNBounded ℝ t
hta : Absorbent ℝ t
⊢ Tendsto (fun x => gauge s x) (𝓝 0) (𝓝 0)

Tactic:
exact tendsto_gauge_nhds_zero hs₀

Result:
no goals

Proof state:
E : Type u_1
inst✝⁵ : AddCommGroup E
inst✝⁴ : Module ℝ E
inst✝³ : TopologicalSpace E
inst✝² : IsTopologicalAddGroup E
inst✝¹ : ContinuousSMul ℝ E
inst✝ : T1Space E
s t : Set E
hs : Convex ℝ s
hs₀ : s ∈ 𝓝 0
ht : Convex ℝ t
ht₀ : t ∈ 𝓝 0
htb : IsVonNBounded ℝ t
hta : Absorbent ℝ t
⊢ Continuous (gaugeRescale s t)

Tactic:
refine continuous_iff_continuousAt.2 fun x ↦ ?_

Result:
E : Type u_1
inst✝⁵ : AddCommGroup E
inst✝⁴ : Module ℝ E
inst✝³ : TopologicalSpace E
inst✝² : IsTopologicalAddGroup E
inst✝¹ : ContinuousSMul ℝ E
inst✝ : T1Space E
s t : Set E
hs : Convex ℝ s
hs₀ : s ∈ 𝓝 0
ht : Convex ℝ t
ht₀ : t ∈ 𝓝 0
htb : IsVonNBounded ℝ t
hta : Absorbent ℝ t
x : E
⊢ ContinuousAt (gaugeRescale s t) x

Proof state:
case inl
E : Type u_1
inst✝⁵ : AddCommGroup E
inst✝⁴ : Module ℝ E
inst✝³ : TopologicalSpace E
inst✝² : IsTopologicalAddGroup E
inst✝¹ : ContinuousSMul ℝ E
inst✝ : T1Space E
s t : Set E
hs : Convex ℝ s
hs₀ : s ∈ 𝓝 0
ht : Convex ℝ t
ht₀ : t ∈ 𝓝 0
htb : IsVonNBounded ℝ t
hta : Absorbent ℝ t
⊢ Tendsto (gaugeRescale s t) (𝓝 0) (𝓝 0)

Tactic:
nth_rewrite 2 [← comap_gauge_nhds_zero htb ht₀]

Result:
case inl
E : Type u_1
inst✝⁵ : AddCommGroup E
inst✝⁴ : Module ℝ E
inst✝³ : TopologicalSpace E
inst✝² : IsTopologicalAddGroup E
inst✝¹ : ContinuousSMul ℝ E
inst✝ : T1Space E
s t : Set E
hs : Convex ℝ s
hs₀ : s ∈ 𝓝 0
ht : Convex ℝ t
ht₀ : t ∈ 𝓝 0
htb : IsVonNBounded ℝ t
hta : Absorbent ℝ t
⊢ Tendsto (gaugeRescale s t) (𝓝 0) (comap (gauge t) (𝓝 0))

Proof state:
case inl
E : Type u_1
inst✝⁵ : AddCommGroup E
inst✝⁴ : Module ℝ E
inst✝³ : TopologicalSpace E
inst✝² : IsTopologicalAddGroup E
inst✝¹ : ContinuousSMul ℝ E
inst✝ : T1Space E
s t : Set E
hs : Convex ℝ s
hs₀ : s ∈ 𝓝 0
ht : Convex ℝ t
ht₀ : t ∈ 𝓝 0
htb : IsVonNBounded ℝ t
hta : Absorbent ℝ t
⊢ ContinuousAt (gaugeRescale s t) 0

Tactic:
rw [ContinuousAt, gaugeRescale_zero]

Result:
case inl
E : Type u_1
inst✝⁵ : AddCommGroup E
inst✝⁴ : Module ℝ E
inst✝³ : TopologicalSpace E
inst✝² : IsTopologicalAddGroup E
inst✝¹ : ContinuousSMul ℝ E
inst✝ : T1Space E
s t : Set E
hs : Convex ℝ s
hs₀ : s ∈ 𝓝 0
ht : Convex ℝ t
ht₀ : t ∈ 𝓝 0
htb : IsVonNBounded ℝ t
hta : Absorbent ℝ t
⊢ Tendsto (gaugeRescale s t) (𝓝 0) (𝓝 0)

Proof state:
case inl
E : Type u_1
inst✝⁵ : AddCommGroup E
inst✝⁴ : Module ℝ E
inst✝³ : TopologicalSpace E
inst✝² : IsTopologicalAddGroup E
inst✝¹ : ContinuousSMul ℝ E
inst✝ : T1Space E
s t : Set E
hs : Convex ℝ s
hs₀ : s ∈ 𝓝 0
ht : Convex ℝ t
ht₀ : t ∈ 𝓝 0
htb : IsVonNBounded ℝ t
hta : Absorbent ℝ t
⊢ Tendsto (gaugeRescale s t) (𝓝 0) (comap (gauge t) (𝓝 0))

Tactic:
simp only [tendsto_comap_iff, Function.comp_def, gauge_gaugeRescale _ hta htb]

Result:
case inl
E : Type u_1
inst✝⁵ : AddCommGroup E
inst✝⁴ : Module ℝ E
inst✝³ : TopologicalSpace E
inst✝² : IsTopologicalAddGroup E
inst✝¹ : ContinuousSMul ℝ E
inst✝ : T1Space E
s t : Set E
hs : Convex ℝ s
hs₀ : s ∈ 𝓝 0
ht : Convex ℝ t
ht₀ : t ∈ 𝓝 0
htb : IsVonNBounded ℝ t
hta : Absorbent ℝ t
⊢ Tendsto (fun x => gauge s x) (𝓝 0) (𝓝 0)

Proof state:
E : Type u_1
inst✝⁵ : AddCommGroup E
inst✝⁴ : Module ℝ E
inst✝³ : TopologicalSpace E
inst✝² : IsTopologicalAddGroup E
inst✝¹ : ContinuousSMul ℝ E
inst✝ : T1Space E
s t : Set E
hs : Convex ℝ s
hs₀ : s ∈ 𝓝 0
ht : Convex ℝ t
ht₀ : t ∈ 𝓝 0
htb : IsVonNBounded ℝ t
hta : Absorbent ℝ t
x : E
⊢ ContinuousAt (gaugeRescale s t) x

Tactic:
rcases eq_or_ne x 0 with rfl | hx

Result:
case inl
E : Type u_1
inst✝⁵ : AddCommGroup E
inst✝⁴ : Module ℝ E
inst✝³ : TopologicalSpace E
inst✝² : IsTopologicalAddGroup E
inst✝¹ : ContinuousSMul ℝ E
inst✝ : T1Space E
s t : Set E
hs : Convex ℝ s
hs₀ : s ∈ 𝓝 0
ht : Convex ℝ t
ht₀ : t ∈ 𝓝 0
htb : IsVonNBounded ℝ t
hta : Absorbent ℝ t
⊢ ContinuousAt (gaugeRescale s t) 0

case inr
E : Type u_1
inst✝⁵ : AddCommGroup E
inst✝⁴ : Module ℝ E
inst✝³ : TopologicalSpace E
inst✝² : IsTopologicalAddGroup E
inst✝¹ : ContinuousSMul ℝ E
inst✝ : T1Space E
s t : Set E
hs : Convex ℝ s
hs₀ : s ∈ 𝓝 0
ht : Convex ℝ t
ht₀ : t ∈ 𝓝 0
htb : IsVonNBounded ℝ t
hta : Absorbent ℝ t
x : E
hx : x ≠ 0
⊢ ContinuousAt (gaugeRescale s t) x