ScalingStacks

Remark 4.20 . [02PW]

Original official author HTML, exact retained edition. Historical TeX conversion verdicts remain unchanged. Cited-edition alignment and mathematical self-containment are not assessed.

Complete original source context · Original author HTML

Remark 4.20.

The terminology “toric structure”, “toric line bundle” and “toric section” comes from the fact that the total space of a toric line bundle V⁡(L)=𝐒𝐩𝐞𝐜X⁡(Sym⁡(L∨))V(L)=\operatorname{\bf Spec}_{X}(\operatorname{Sym}(L^{\vee})) admits a unique structure of toric variety satisfying the conditions:

  1. (1)

    zz is the distinguished point of the principal open subset;

  2. (2)

    the structural morphism V⁡(L)→XV(L)\to X is a toric morphism;

  3. (3)

    for each point x∈Xx\in X and vector w∈Lxw\in L_{x}, the morphism 𝔾m→V⁡(L)\mathbb{G}_{m}\to V(L), given by scalar multiplication λ↦λ​w\lambda\mapsto\lambda w, is equivariant;

  4. (4)

    every toric section ss determines a toric morphism U→V⁡(L)U\to V(L), where UU is the invariant open subset of regular points of ss.

This can be shown using the construction of V⁡(L)V(L) as a toric variety in [Oda88, Proposition 2.1].

Original mathematics by the credited authors. Source-backed reader collection; mathematical self-containment is not assessed.