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Related papers: Boundedness and volume of generalised pairs

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In this paper we investigate various properties of generalised pairs in families, especially boundedness of several kinds. We show that many statements for usual pairs do not hold for generalised pairs. In particular, we construct an…

Algebraic Geometry · Mathematics 2022-04-25 Caucher Birkar , Christopher D. Hacon

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

In this paper, we study the behavior of the sets of volumes of the form $\mathrm{vol}(X,K_X+B+M)$, where $(X,B)$ is a log canonical pair, and $M$ is a nef $\mathbb{R}$-divisor. After a first analysis of some general properties, we focus on…

Algebraic Geometry · Mathematics 2021-08-12 Stefano Filipazzi

We investigate the DCC property of the set of Iitaka volumes of a given set of pairs of varieties. We both generalize previous results of Birkar and Li about usual pairs to the real coefficient case, and also establish similar results on…

Algebraic Geometry · Mathematics 2026-05-19 Pinxian Bie

We investigate the singularities and boundedness of a special kind of algebraic varieties so-called stable minimal models, which are constructed and studied by Birkar. Given a klt stable minimal model with bounded relative volume, if we fix…

Algebraic Geometry · Mathematics 2025-01-30 Minzhe Zhu

We show that the family of semi log canonical pairs with ample log canonical class and with fixed volume is bounded.

Algebraic Geometry · Mathematics 2017-09-22 Christopher Hacon , James McKernan , Chenyang Xu

It is conjectured that the canonical models of varieties (not of general type) are bounded when the Iitaka volume is fixed. We confirm this conjecture when the general fibers of the corresponding Iitaka fibration are in a fixed bounded…

Algebraic Geometry · Mathematics 2025-09-17 Junpeng Jiao

Given a pair $(V,C)$ that admits a stable minimal model with fixed dimension, fixed coefficient set, and bounded relative volume, we study when the linear system $|m(K_V+C)|$ induces an Iitaka fibration, assuming the Iitaka volume of…

Algebraic Geometry · Mathematics 2026-03-30 Hexu Liu

In this paper, we study the volume of algebraically integrable foliations and locally stable families. We show that, for any canonical algebraically integrable foliation, its volume belongs to a discrete set depending only on its rank and…

Algebraic Geometry · Mathematics 2024-06-25 Jingjun Han , Junpeng Jiao , Mengchu Li , Jihao Liu

We study the volumes of divisors in Calabi--Yau type varieties. We show that given a klt Calabi--Yau pair $(X,B)$ and an integral divisor $A$ on $X$, the volume of $A$ is in a fixed discrete set depending only on the dimension and…

Algebraic Geometry · Mathematics 2025-08-08 Junpeng Jiao

We prove some basic properties of the relative Nakayama-Zariski decomposition. We apply them to the study of lc generalized pairs. We prove the existence of log minimal models or Mori fiber spaces for (relative) lc generalized pairs…

Algebraic Geometry · Mathematics 2023-05-23 Jihao Liu , Lingyao Xie

Let $X$ be a normal projective variety defined over an algebraically closed field and let $Z$ be a subvariety. Let $D$ be an $\mathbb R$-Cartier $\mathbb R$-divisor on $X$. Given an expression $(\ast) \ D \sim_{\mathbb R} t_1 H_1 + \ldots +…

Algebraic Geometry · Mathematics 2015-10-28 Angelo Felice Lopez

In this note, we survey some recent developments in birational geometry concerning the boundedness of algebraic varieties. We delineate a strategy to extend some of these results to the case of generalized pairs, first introduced by Birkar…

Algebraic Geometry · Mathematics 2022-03-02 Stefano Filipazzi , Roberto Svaldi

In this article we prove the following boundedness result: Fix a DCC set $I\subset [0, 1]$. Let $\mathfrak{D}$ be the set of all log pairs $(X, \Delta)$ satisfying the following properties: (i) $X$ is a projective surface defined over an…

Algebraic Geometry · Mathematics 2020-11-10 Omprokash Das

We prove that normal projective stable families of maximal variation, of fixed dimension, and with bounded adjoint volume are birationally bounded. This is a consequence of a substantially stronger statement, formulated a priori…

Algebraic Geometry · Mathematics 2026-04-28 Paolo Cascini , Jihao Liu , Calum Spicer , Roberto Svaldi

We prove an analogue of Fujino and Mori's ``bounding the denominators'' in the log canonical bundle formula (see also Prokhorov and Shokurov) for Kawamata log terminal pairs of relative dimension one. As an application we prove that for a…

Algebraic Geometry · Mathematics 2008-05-23 Gueorgui Todorov

We prove new boundedness results across different areas of algebraic geometry, stemming from a unifying technical starting point: bounding the integer $q > 0$ such that the $q$-th Hodge bundle becomes (semi-)positive for families of stable…

Algebraic Geometry · Mathematics 2025-08-04 Giulio Codogni , Zsolt Patakfalvi , Luca Tasin

For good minimal models with klt singularities, polarized by Weil divisors that are relatively nef and big over the bases of the Iitaka fibration, we show that, after fixing appropriate numerical invariants, they form a bounded family. As…

Algebraic Geometry · Mathematics 2025-08-19 Xiaowei Jiang

Given positive integers $d\geq\kappa$, and a subset $\Gamma\subset [0,1]$, let $\mathrm{Ivol}_{\mathrm{lc}}^{\Gamma}(d,\kappa)$ denote the set of Iitaka volumes of $d$-dimensional projective log canonical pairs $(X, B)$ such that the…

Algebraic Geometry · Mathematics 2024-07-11 Guodu Chen , Jingjun Han , Wenfei Liu

Let (X_0,B_0) be the canonical limit of a one-parameter family of stable pairs, provided by the log Minimal Model Program. We prove that X_0 is S2 and that [B_0] is S_1, as an application of a general local statement: if (X,B+\epsilon D) is…

Algebraic Geometry · Mathematics 2007-11-05 Valery Alexeev
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