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We present an explicit expression for the normalized height of a projective toric variety. This expression decomposes as a sum of local contributions, each term being the integral of a certain function, concave and piecewise linear-affine.…

Number Theory · Mathematics 2007-05-23 Patrice Philippon , Martin Sombra

We establish strong factorization for pairs of smooth fans which are refined by the braid arrangement fan. Our method uses a correspondence between cones and preposets.

Algebraic Geometry · Mathematics 2021-03-26 John Machacek

We prove that special ample line bundles on toric varieties arising from root systems are projectively normal. Here the maximal cones of the fans correspond to the Weyl chambers, and special means that the bundle is torus-equivariant such…

Algebraic Geometry · Mathematics 2011-02-22 Qëndrim R. Gashi , Travis Schedler

For a connected smooth projective curve $X$ of genus $g$, global sections of any line bundle $L$ with $\deg(L) \geq 2g+ 1$ give an embedding of the curve into projective space. We consider an analogous statement for a Berkovich skeleton in…

Algebraic Geometry · Mathematics 2017-04-07 Shu Kawaguchi , Kazuhiko Yamaki

Traditional algorithms for stochastic optimization require projecting the solution at each iteration into a given domain to ensure its feasibility. When facing complex domains, such as positive semi-definite cones, the projection operation…

Machine Learning · Computer Science 2013-04-03 Lijun Zhang , Tianbao Yang , Rong Jin , Xiaofei He

Let $\Sigma$ and $\Sigma'$ be two refinements of a fan $\Sigma_0$ and $f \colon X_{\Sigma} \dashrightarrow X_{\Sigma'}$ be the birational map induced by $X_{\Sigma} \rightarrow X_{\Sigma_0} \leftarrow X_{\Sigma'}$. We show that the graph…

Algebraic Geometry · Mathematics 2025-02-13 Tsung-Chen Chen , Hui-Wen Lin , Sz-Sheng Wang

This is a pdf print of the homonymous Maple file, freely available at http://www.maplesoft.com/applications/view.aspx?SID=127621, providing procedures which are able to produce the toric data associated with a (polarized) weighted…

Algebraic Geometry · Mathematics 2011-12-08 Michele Rossi , Lea Terracini

Inspired by Fujita's algebro-geometric result that complex projective space has maximal degree among all K-semistable complex Fano varieties, we conjecture that the height of a K-semistable metrized arithmetic Fano variety X of relative…

Algebraic Geometry · Mathematics 2024-11-20 Rolf Andreasson , Robert J. Berman

We propose a canonical local-to-global lattice theory for rational fans. We define the $\textit{ray lattice } L_{\mathrm{rays}}(\Sigma)$ and the $\textit{relation lattice } L_{\mathrm{rel}}(\Sigma)$ as invariants functorial under fan…

Combinatorics · Mathematics 2026-01-12 Rizwan Jahangir

Let $F$ be a torsionfree semistable coherent sheaf on a polarized normal projective variety. We prove that $F$ has a unique maximal locally free subsheaf $V$ such that $F/V$ is torsionfree and $V$ admits a filtration of subbundles for which…

Algebraic Geometry · Mathematics 2021-06-08 Indranil Biswas , A. J. Parameswaran

We construct combinatorial bases of the $T$-equivariant ($T$ is the maximal torus) cohomology $H^\bullet_T(\Sigma,k)$ of the Bott-Samelson variety $\Sigma$ under some mild restrictions on the field of coefficients $k$. This bases allow us…

Representation Theory · Mathematics 2016-01-27 Vladimir Shchigolev

We survey a collection of closely related methods for generalizing fans of toric varieties, include skeletons, Kato fans, Artin fans, and polyhedral cone complexes, all of which apply in the wider context of logarithmic geometry. Under…

Algebraic Geometry · Mathematics 2015-06-30 Dan Abramovich , Qile Chen , Steffen Marcus , Martin Ulirsch , Jonathan Wise

Let $\Sigma$ be a fan inside the lattice $\mathbb{Z}^n$, and $\mathcal{E}:\mathbb{Z}^n \rightarrow \operatorname{Pic}{S}$ be a map of abelian groups. We introduce the notion of a principal toric fibration $\mathcal{X}_{\Sigma, \mathcal{E}}$…

Algebraic Geometry · Mathematics 2023-04-04 Yuxuan Hu , Pyongwon Suh

We propose new definitions of integral, reduced, and normal superrings and superschemes to properly establish the notion of a supervariety. We generalize several results about classical reduced rings and varieties to the supergeometric…

Algebraic Geometry · Mathematics 2025-03-11 Eric Jankowski

This note proves the existence of universal rational parametrizations. The description involves homogeneous coordinates on a toric variety coming from a lattice polytope. We first describe how smooth toric varieties lead to universal…

Algebraic Geometry · Mathematics 2007-05-23 David Cox , Rimvydas Krasauskas , Mircea Mustata

The space of torus translations and degenerations of a projective toric variety forms a toric variety associated to the secondary fan of the integer points in the polytope corresponding to the toric variety. This is used to identify a…

Algebraic Geometry · Mathematics 2020-12-22 Ata Pir , Frank Sottile

Let X be a plane in a torus over an algebraically closed field K, with tropicalization the matroidal fan Sigma. In this paper we present an algorithm which completely solves the question whether a given one-dimensional balanced polyhedral…

Algebraic Geometry · Mathematics 2014-12-10 Anna Lena Birkmeyer , Andreas Gathmann

We exhibit full exceptional collections of vector bundles on any smooth, Fano arithmetic toric variety whose split fan is centrally symmetric.

Algebraic Geometry · Mathematics 2020-06-17 Matthew R Ballard , Alexander Duncan , Patrick K. McFaddin

We give an explicit description of all smooth varieties with a torus action of complexity one having Picard number at most two. As a consequence, we classify in every dimension the smooth (almost) Fano varieties with a torus action of…

Algebraic Geometry · Mathematics 2025-07-08 Anne Fahrner , Juergen Hausen , Michele Nicolussi

In this paper, we investigate $C^2$ super-smoothness of the full $C^1$ cubic spline space on a Powell-Sabin refined triangulation, for which a B-spline basis can be constructed. Blossoming is used to identify the $C^2$ smoothness conditions…

Numerical Analysis · Mathematics 2024-11-11 Jan Grošelj , Hendrik Speleers