English
If f is bijective, then CauchySeq(u ∘ f) ⇔ CauchySeq u.
Русский
Если f биективно отображает, тогда CauchySeq(u∘f) равно CauchySeq u.
LaTeX
$$$\\text{CauchySeq}(u\\circ f) \\iff \\text{CauchySeq}(u)$, при биективности f.$$
Lean4
theorem comp_tendsto {γ} [Preorder β] [SemilatticeSup γ] [Nonempty γ] {f : β → α} (hf : CauchySeq f) {g : γ → β}
(hg : Tendsto g atTop atTop) : CauchySeq (f ∘ g) :=
⟨inferInstance, le_trans (prod_le_prod.mpr ⟨Tendsto.comp le_rfl hg, Tendsto.comp le_rfl hg⟩) hf.2⟩