Embeddings of weighted projective spaces

Fuente: arXiv
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Main Authors: Adeyemo, Praise, Bunnett, Dominic, Levicán-Santibáñez, Fabián
Format: Preprint
Published: 2025
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author Adeyemo, Praise
Bunnett, Dominic
Levicán-Santibáñez, Fabián
author_facet Adeyemo, Praise
Bunnett, Dominic
Levicán-Santibáñez, Fabián
contents Let $X$ be a projective toric variety of dimension $n$ and let $L$ be a ample line bundle on $X$. For $k \geq 0$, it is in general difficult to determine whether $L^{\otimes k}$ is very ample and whether it additionally gives a projectively normal embedding. These two properties are equivalent to the very ampleness, respectively normality, of the corresponding polytope. By a result of Ewald-Wessels, both statements are classically known to hold for $k \geq n - 1$. We study embeddings of weighted projective spaces $\mathbb{P}(a_0, ..., a_n)$ via their corresponding rectangular simplices $Δ(λ_1, ..., λ_n)$. We give multiple criteria (depending on arithmetic properties of the weights $a_i$) to obtain bounds for the power $k$ which are sharp in many cases. We also introduce combinatorial tools that allow us to systematically construct families exhibiting extremal behaviour. These results extend earlier work of Payne, Hering and Bruns-Gubeladze.
format Preprint
id arxiv_https___arxiv_org_abs_2510_05076
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Embeddings of weighted projective spaces
Adeyemo, Praise
Bunnett, Dominic
Levicán-Santibáñez, Fabián
Algebraic Geometry
Combinatorics
Let $X$ be a projective toric variety of dimension $n$ and let $L$ be a ample line bundle on $X$. For $k \geq 0$, it is in general difficult to determine whether $L^{\otimes k}$ is very ample and whether it additionally gives a projectively normal embedding. These two properties are equivalent to the very ampleness, respectively normality, of the corresponding polytope. By a result of Ewald-Wessels, both statements are classically known to hold for $k \geq n - 1$. We study embeddings of weighted projective spaces $\mathbb{P}(a_0, ..., a_n)$ via their corresponding rectangular simplices $Δ(λ_1, ..., λ_n)$. We give multiple criteria (depending on arithmetic properties of the weights $a_i$) to obtain bounds for the power $k$ which are sharp in many cases. We also introduce combinatorial tools that allow us to systematically construct families exhibiting extremal behaviour. These results extend earlier work of Payne, Hering and Bruns-Gubeladze.
title Embeddings of weighted projective spaces
topic Algebraic Geometry
Combinatorics
url https://arxiv.org/abs/2510.05076