sum — Mathlib

English

The sum of two pointings keeps the left component from p and the right component from q: fst := Sum.inl p.fst, snd := Sum.inr q.snd.

Русский

Сумма двух указателей сохраняет левую точку из p и правую точку из q: fst := Sum.inl p.fst, snd := Sum.inr q.snd.

LaTeX

$$The sum of two pointings is a TwoPointing on $\\alpha \\oplus \\beta$ with fst := Sum.inl(p.fst) and snd := Sum.inr(q.snd).$$

Lean4

/-- The sum of two pointings. Keeps the first point from the left and the second point from the
right. -/
protected def sum : TwoPointing (α ⊕ β) :=
  ⟨(Sum.inl p.fst, Sum.inr q.snd), Sum.inl_ne_inr⟩

Похожие утверждения