English
If ι is finite, equicontinuity within S at x0 is equivalent to all F_i being continuous within S at x0.
Русский
Если ι конечно, эконтинуальность внутри S в x0 эквивалентна тому, что каждый F_i непрерывен внутри S в x0.
LaTeX
$$$$ [Finite ι]\ EquicontinuousWithinAt F S x_0 \iff \forall i, ContinuousWithinAt (F i) S x_0. $$$$
Lean4
theorem equicontinuousWithinAt_finite [Finite ι] {F : ι → X → α} {S : Set X} {x₀ : X} :
EquicontinuousWithinAt F S x₀ ↔ ∀ i, ContinuousWithinAt (F i) S x₀ := by
simp [EquicontinuousWithinAt, ContinuousWithinAt, (nhds_basis_uniformity' (𝓤 α).basis_sets).tendsto_right_iff,
UniformSpace.ball, @forall_swap _ ι]