English
The zero locus of a set s of sections over an open U is the set of points where all sections in s vanish; equivalently, Z(s) = ⋂_{f∈s} (D(f))^c.
Русский
Нулевая локация множества секций s над открытым U — множество точек, где все секции из s обращаются в ноль; то есть Z(s) = ⋂_{f∈s} (D(f))^c.
LaTeX
$$$X$ is a ringed space, $U$ an open subset, and $s \subseteq \mathcal{O}_X(U)$. Then$$
Lean4
/-- The zero locus of a set of sections `s` over an open set `U` is the closed set consisting of
the complement of `U` and of all points of `U`, where all elements of `f` vanish.
-/
def zeroLocus {U : Opens X} (s : Set (X.presheaf.obj (op U))) : Set X :=
⋂ f ∈ s, (X.basicOpen f)ᶜ