English
There exists a canonical lifting from pairs (a,b) with a ≤ b to NonemptyInterval α via toProd.
Русский
Существует каноническое подъёмное отображение от пары (a,b) с a ≤ b к NonemptyInterval α через toProd.
LaTeX
$$∃ s ∈ NonemptyInterval α, toProd s = (a,b) whenever a ≤ b$$
Lean4
/-- Allow lifting a pair `(a, b)` with `a ≤ b` to `NonemptyInterval`
in the `lift` tactic. -/
instance instCanLift : CanLift (α × α) (NonemptyInterval α) NonemptyInterval.toProd (fun x ↦ x.1 ≤ x.2) where
prf x hx := ⟨⟨x, hx⟩, rfl⟩