English
Let β be a ConditionallyCompleteLattice and f : α → β be monotone. If s ⊆ α is nonempty, then f(sInf s) = sInf (f'' s).
Русский
Пусть β — условно полноупорядоченная решетка, f: α → β монотонно. Если s непусто, то f(Inf s) = Inf( f'' s ).
LaTeX
$$$f(sInf(s)) = sInf(f''s) \quad\text{if } s \neq \varnothing$$$
Lean4
theorem map_csInf {β : Type*} [ConditionallyCompleteLattice β] {f : α → β} (hf : Monotone f) (hs : s.Nonempty) :
f (sInf s) = sInf (f '' s) :=
(hf.map_isLeast (isLeast_csInf hs)).csInf_eq.symm