-- Mathlib/Topology/Algebra/Order/Floor.lean
theorem ContinuousOn.comp_fract' {f : β → α → γ} (h : ContinuousOn (uncurry f) <| univ ×ˢ I)
    (hf : ∀ s, f s 0 = f s 1) : Continuous fun st : β × α => f st.1 (fract st.2)

Proof state:
case mk.inl.intro
α : Type u_1
β : Type u_2
γ : Type u_3
inst✝⁵ : LinearOrderedRing α
inst✝⁴ : FloorRing α
inst✝³ : TopologicalSpace α
inst✝² : OrderTopology α
inst✝¹ : TopologicalSpace β
inst✝ : TopologicalSpace γ
f : β → α → γ
h : ContinuousOn (uncurry f) (univ ×ˢ Icc 0 1)
hf : ∀ (s : β), f s 0 = f s 1
s : β
n : ℤ
⊢ ContinuousAt (uncurry f ∘ Prod.map id fract) (s, ↑n)

Tactic:
rw [ContinuousAt, nhds_prod_eq, ← nhdsLT_sup_nhdsGE (n : α), prod_sup, tendsto_sup]

Result:
case mk.inl.intro
α : Type u_1
β : Type u_2
γ : Type u_3
inst✝⁵ : LinearOrderedRing α
inst✝⁴ : FloorRing α
inst✝³ : TopologicalSpace α
inst✝² : OrderTopology α
inst✝¹ : TopologicalSpace β
inst✝ : TopologicalSpace γ
f : β → α → γ
h : ContinuousOn (uncurry f) (univ ×ˢ Icc 0 1)
hf : ∀ (s : β), f s 0 = f s 1
s : β
n : ℤ
⊢ Tendsto (uncurry f ∘ Prod.map id fract) (𝓝 s ×ˢ 𝓝[<] ↑n) (𝓝 ((uncurry f ∘ Prod.map id fract) (s, ↑n))) ∧
    Tendsto (uncurry f ∘ Prod.map id fract) (𝓝 s ×ˢ 𝓝[≥] ↑n) (𝓝 ((uncurry f ∘ Prod.map id fract) (s, ↑n)))

Proof state:
case mk.inl.intro.right
α : Type u_1
β : Type u_2
γ : Type u_3
inst✝⁵ : LinearOrderedRing α
inst✝⁴ : FloorRing α
inst✝³ : TopologicalSpace α
inst✝² : OrderTopology α
inst✝¹ : TopologicalSpace β
inst✝ : TopologicalSpace γ
f : β → α → γ
h : ContinuousOn (uncurry f) (univ ×ˢ Icc 0 1)
hf : ∀ (s : β), f s 0 = f s 1
s : β
n : ℤ
⊢ Tendsto (uncurry f ∘ Prod.map id fract) (𝓝 s ×ˢ 𝓝[≥] ↑n) (𝓝 ((uncurry f ∘ Prod.map id fract) (s, ↑n)))

Tactic:
refine (((h (s, 0) ⟨trivial, le_rfl, zero_le_one⟩).tendsto.mono_left <| le_of_eq ?_).comp
  (tendsto_id.prod_map (tendsto_fract_right _))).mono_right (le_of_eq ?_) <;>
  simp [nhdsWithin_prod_eq, nhdsWithin_univ]

Result:
no goals

Proof state:
case mk.inl.intro
α : Type u_1
β : Type u_2
γ : Type u_3
inst✝⁵ : LinearOrderedRing α
inst✝⁴ : FloorRing α
inst✝³ : TopologicalSpace α
inst✝² : OrderTopology α
inst✝¹ : TopologicalSpace β
inst✝ : TopologicalSpace γ
f : β → α → γ
h : ContinuousOn (uncurry f) (univ ×ˢ Icc 0 1)
hf : ∀ (s : β), f s 0 = f s 1
s : β
n : ℤ
⊢ Tendsto (uncurry f ∘ Prod.map id fract) (𝓝 s ×ˢ 𝓝[<] ↑n) (𝓝 ((uncurry f ∘ Prod.map id fract) (s, ↑n))) ∧
    Tendsto (uncurry f ∘ Prod.map id fract) (𝓝 s ×ˢ 𝓝[≥] ↑n) (𝓝 ((uncurry f ∘ Prod.map id fract) (s, ↑n)))

Tactic:
constructor

Result:
case mk.inl.intro.left
α : Type u_1
β : Type u_2
γ : Type u_3
inst✝⁵ : LinearOrderedRing α
inst✝⁴ : FloorRing α
inst✝³ : TopologicalSpace α
inst✝² : OrderTopology α
inst✝¹ : TopologicalSpace β
inst✝ : TopologicalSpace γ
f : β → α → γ
h : ContinuousOn (uncurry f) (univ ×ˢ Icc 0 1)
hf : ∀ (s : β), f s 0 = f s 1
s : β
n : ℤ
⊢ Tendsto (uncurry f ∘ Prod.map id fract) (𝓝 s ×ˢ 𝓝[<] ↑n) (𝓝 ((uncurry f ∘ Prod.map id fract) (s, ↑n)))

case mk.inl.intro.right
α : Type u_1
β : Type u_2
γ : Type u_3
inst✝⁵ : LinearOrderedRing α
inst✝⁴ : FloorRing α
inst✝³ : TopologicalSpace α
inst✝² : OrderTopology α
inst✝¹ : TopologicalSpace β
inst✝ : TopologicalSpace γ
f : β → α → γ
h : ContinuousOn (uncurry f) (univ ×ˢ Icc 0 1)
hf : ∀ (s : β), f s 0 = f s 1
s : β
n : ℤ
⊢ Tendsto (uncurry f ∘ Prod.map id fract) (𝓝 s ×ˢ 𝓝[≥] ↑n) (𝓝 ((uncurry f ∘ Prod.map id fract) (s, ↑n)))

Proof state:
case mk.inl.intro.left.refine_2
α : Type u_1
β : Type u_2
γ : Type u_3
inst✝⁵ : LinearOrderedRing α
inst✝⁴ : FloorRing α
inst✝³ : TopologicalSpace α
inst✝² : OrderTopology α
inst✝¹ : TopologicalSpace β
inst✝ : TopologicalSpace γ
f : β → α → γ
h : ContinuousOn (uncurry f) (univ ×ˢ Icc 0 1)
hf : ∀ (s : β), f s 0 = f s 1
s : β
n : ℤ
⊢ 𝓝 (uncurry f (s, 1)) = 𝓝 ((uncurry f ∘ Prod.map id fract) (s, ↑n))

Tactic:
simp [hf]

Result:
no goals

Proof state:
α : Type u_1
β : Type u_2
γ : Type u_3
inst✝⁵ : LinearOrderedRing α
inst✝⁴ : FloorRing α
inst✝³ : TopologicalSpace α
inst✝² : OrderTopology α
inst✝¹ : TopologicalSpace β
inst✝ : TopologicalSpace γ
f : β → α → γ
h : ContinuousOn (uncurry f) (univ ×ˢ Icc 0 1)
hf : ∀ (s : β), f s 0 = f s 1
⊢ Continuous (uncurry f ∘ Prod.map id fract)

Tactic:
rw [continuous_iff_continuousAt]

Result:
α : Type u_1
β : Type u_2
γ : Type u_3
inst✝⁵ : LinearOrderedRing α
inst✝⁴ : FloorRing α
inst✝³ : TopologicalSpace α
inst✝² : OrderTopology α
inst✝¹ : TopologicalSpace β
inst✝ : TopologicalSpace γ
f : β → α → γ
h : ContinuousOn (uncurry f) (univ ×ˢ Icc 0 1)
hf : ∀ (s : β), f s 0 = f s 1
⊢ ∀ (x : β × α), ContinuousAt (uncurry f ∘ Prod.map id fract) x