English
For posets α and β with InfSet structure, the infimum set in α×β is obtained componentwise from the infima in α and β: InfSet(α×β) s = (sInf fst''s, sInf snd''s).
Русский
Для частично упорядоченных множеств α и β с структурой инфимума, инфимума множества в α×β задаётся по компонентам: InfSet(α×β) s = (sInf fst''s, sInf snd''s).
LaTeX
$$$[InfSet\\ α][InfSet\\ β] \\to\\ InfSet(\\mathrm{Prod}\\ α β): s \\mapsto (sInf (\\mathrm{fst}'' s),\\ sInf (\\mathrm{snd}'' s))$$$
Lean4
instance infSet [InfSet α] [InfSet β] : InfSet (α × β) :=
⟨fun s => (sInf (Prod.fst '' s), sInf (Prod.snd '' s))⟩