no goals
α : Type u_1
β : Type ?u.5916
inst✝ : Preorder α
s t : Set α
Ixx : α → α → Set α
⊢ Tendsto (fun p => Ixx p.fst p.snd) (𝓟 s ×ˢ 𝓟 s) (smallSets (𝓟 t)) ↔ ∀ (x : α), x ∈ s → ∀ (y : α), y ∈ s → Ixx x y ⊆ t
simp only [smallSets_principal, prod_principal_principal, tendsto_principal_principal,
  forall_prod_set, mem_powerset_iff, mem_principal]