English
Addition on ℚ is uniformly continuous: the map (p,q) ↦ p+q is uniformly continuous from ℚ×ℚ to ℚ.
Русский
Сложение в ℚ равномерно непрерывно: отображение (p,q) ↦ p+q из ℚ×ℚ в ℚ является равномерно непрерывным.
LaTeX
$$$\\operatorname{UniformContinuous}(+): \\mathbb{Q} \\times \\mathbb{Q} \ o \\mathbb{Q}$$$
Lean4
theorem uniformContinuous_add : UniformContinuous fun p : ℚ × ℚ => p.1 + p.2 :=
Rat.isUniformEmbedding_coe_real.isUniformInducing.uniformContinuous_iff.2 <|
by
simp only [Function.comp_def, Rat.cast_add]
exact Real.uniformContinuous_add.comp (Rat.uniformContinuous_coe_real.prodMap Rat.uniformContinuous_coe_real)