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Related papers: The Log Minimal Model Program for horospherical va…

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We discuss the relative log minimal model theory for log surfaces in the analytic setting. More precisely, we show that the minimal model program, the abundance theorem, and the finite generation of log canonical rings hold for log pairs of…

Algebraic Geometry · Mathematics 2026-04-15 Nao Moriyama

We describe smooth projective horospherical varieties with Picard number 1. Moreover we prove that the automorphism group of any such variety acts with at most two orbits and we give a geometric characterisation of non-homogeneous ones.

Algebraic Geometry · Mathematics 2007-05-23 Boris Pasquier

We extend to characteristic $2$ and $3$ the classification of projective homogeneous varieties of Picard group isomorphic to $\mathbf{Z}$, corresponding to parabolic subgroup schemes with maximal reduced subgroup. The latter are all…

Algebraic Geometry · Mathematics 2023-06-27 Matilde Maccan

In this paper we describe orbits of automorphism group on a horospherical variety in terms of degrees of homogeneous with respect to natural grading locally nilpotent derivations. In case of (may be non-normal) toric varieties a description…

Algebraic Geometry · Mathematics 2021-05-14 Viktoriia Borovik , Sergey Gaifullin , Anton Shafarevich

Let $(X,\Delta)$ be a normal pair with a projective morphism $X \to Z$ and let $A$ be a relatively ample $\mathbb{R}$-divisor on $X$. We prove the termination of some minimal model program on $(X,\Delta+A)/Z$ and the abundance conjecture…

Algebraic Geometry · Mathematics 2025-10-21 Kenta Hashizume

This semi-expository paper discusses the log minimal model program as applied to the moduli space of curves, especially in the case of curves of genus two. Log canonical models for these moduli spaces can often be constructed using the…

Algebraic Geometry · Mathematics 2007-05-23 Brendan Hassett

We show that minimal models of log canonical pairs exist, assuming the existence of minimal models of smooth varieties.

Algebraic Geometry · Mathematics 2022-05-24 Vladimir Lazić , Nikolaos Tsakanikas

We describe the foundation of the log minimal model program for log canonical pairs according to Ambro's idea. We generalize Koll\'ar's vanishing and torsion-free theorems for embedded simple normal crossing pairs. Then we prove the cone…

Algebraic Geometry · Mathematics 2009-07-10 Osamu Fujino

We discuss the minimal model program for projective morphisms of complex analytic spaces. Roughly speaking, we show that the results obtained by Birkar--Cascini--Hacon--M\textsuperscript{c}Kernan hold true for projective morphisms between…

Algebraic Geometry · Mathematics 2022-01-28 Osamu Fujino

We show that the number of marked minimal models of an n-dimensional smooth complex projective variety of general type can be bounded in terms of its volume, and, if n=3, also in terms of its Betti numbers. For an n-dimensional projective…

Algebraic Geometry · Mathematics 2020-11-30 Diletta Martinelli , Stefan Schreieder , Luca Tasin

We compute the divisor class group and the Picard group of projective varieties with Hibi rings as homogeneous coordinate rings. These varieties are precisely the toric varieties associated to order polytopes. We use tools from the theory…

Algebraic Geometry · Mathematics 2015-06-09 Tobias Friedl

We discuss an experimental approach to open problems in toric geometry: are smooth projective toric varieties (i) projectively normal and (ii) defined by degree 2 equations? We discuss the creation of lattice polytopes defining smooth toric…

Algebraic Geometry · Mathematics 2013-01-29 Winfried Bruns

Our main result is a combinatorial characterization of when a horospherical variety has (at worst) quotient singularities. Using this characterization, we show that every quasiprojective horospherical variety with quotient singularities is…

Algebraic Geometry · Mathematics 2026-03-31 Sean Monahan

When the standard representation of a crystallographic Coxeter group G (with string diagram) is reduced modulo the integer d>1, one obtains a finite group G^d which is often the automorphism group of an abstract regular polytope. Building…

Combinatorics · Mathematics 2008-05-23 B. Monson , Egon Schulte

We study the arithmetic properties of projective varieties of almost minimal degree, that is of non-degenerate irreducible projective varieties whose degree exceeds the codimension by precisely 2. We notably show, that such a variety $X…

Commutative Algebra · Mathematics 2007-05-23 Markus Brodmann , Peter Schenzel

We construct a moduli space of stable projective pairs with a nontrivial action of a connected reductive group. These stable reductive pairs are higher-dimensional analogs of stable n-pointed curves and generalize to the non-commutative…

Algebraic Geometry · Mathematics 2007-05-23 Valery Alexeev , Michel Brion

Under the assumption of the minimal model theory for projective klt pairs of dimension $n$, we establish the minimal model theory for lc pairs $(X/Z,\Delta)$ such that the log canonical divisor is relatively log abundant and its restriction…

Algebraic Geometry · Mathematics 2019-08-29 Kenta Hashizume , Zhengyu Hu

Any integral convex polytope $P$ in $\mathbb{R}^N$ provides a $N$-dimensional toric variety $X_P$ and an ample divisor $D_P$ on this variety. This paper gives an explicit construction of the algebraic geometric error-correcting code on…

Algebraic Geometry · Mathematics 2021-02-08 Jade Nardi

The main purpose of this paper is to give a simple and non-combinatorial proof of the toric Mori theory. Here, the toric Mori theory means the (log) Minimal Model Program (MMP, for short) for toric varieties. We minimize the arguments on…

Algebraic Geometry · Mathematics 2016-09-07 Osamu Fujino , Hiroshi Sato

In this article, we establish the existence of a good minimal model for a compact K\"ahler klt pair $(X, B)$ when the Albanese map of $X$ is a projective morphism and the general fiber of $(X, B)$ has a good minimal model.

Algebraic Geometry · Mathematics 2026-04-20 Yu-Ting Huang