English
If p is OneOneEquiv to q, then p ≤₁ r is equivalent to q ≤₁ r.
Русский
Если p эквивалентно q, то редуцируемость p к r эквивалентна редуцируемости q к r.
LaTeX
$$$ (p \\sim q) \\Rightarrow (p \\le_1 r \\iff q \\le_1 r) $$$
Lean4
theorem congr_left {α β γ} [Primcodable α] [Primcodable β] [Primcodable γ] {p : α → Prop} {q : β → Prop} {r : γ → Prop}
(h : OneOneEquiv p q) : OneOneEquiv p r ↔ OneOneEquiv q r :=
and_congr h.le_congr_left h.le_congr_right