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Related papers: Boundedness and volume of generalised pairs

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We show that in any $\mathbb{Q}$-Gorenstein flat family of klt singularities, normalized volumes are lower semicontinuous with respect to the Zariski topology. A quick consequence is that smooth points have the largest normalized volume…

Algebraic Geometry · Mathematics 2021-07-14 Harold Blum , Yuchen Liu

1) Assuming log Minimal Model Conjecture, we give a construction of a complete moduli space of stable log pairs of arbitrary dimension generalizing directly the space M_{g,n} of pointed stable curves. Each stable pair has semi log canonical…

alg-geom · Mathematics 2008-02-03 Valery Alexeev

Given an NQC log canonical generalized pair $(X,B+M)$ whose underlying variety $X$ is not necessarily $\mathbb{Q}$-factorial, we show that one may run a $(K_X+B+M)$-MMP with scaling of an ample divisor which terminates, provided that…

Algebraic Geometry · Mathematics 2025-09-19 Nikolaos Tsakanikas , Lingyao Xie

In this paper, we use canonical bundle formulas to prove some generalizations of an old theorem of Kawamata on the semiampleness of nef and abundant log canonical divisors. In particular, we show that for klt pairs $(X,B)$ with $K_X+B$…

Algebraic Geometry · Mathematics 2022-09-07 Priyankur Chaudhuri

We show boundedness of polarized Calabi--Yau fibrations over curves only with fixed volumes of general fibers and Iitaka volumes. As its application, we construct a separated coarse moduli space of K-stable Calabi-Yau fibrations over curves…

Algebraic Geometry · Mathematics 2025-06-11 Kenta Hashizume , Masafumi Hattori

We extend to normal projective varieties defined over an arbitrary algebraically closed field a result of Ein, Lazarsfeld, Musta\c{t}\u{a}, Nakamaye and Popa characterizing the augmented base locus (aka non-ample locus) of a line bundle on…

Algebraic Geometry · Mathematics 2014-12-24 Sébastien Boucksom , Salvatore Cacciola , Angelo Felice Lopez

Let $\epsilon, C$ be two positive real numbers, and $\mathcal C \subset \mathbb R$ be a DCC (descending chain condition) set. Let $(X, B = \sum b_j B_j)$ denote a projective surface with an $\mathbb R$-divisor. Then (1) The class $\{X\}$ of…

alg-geom · Mathematics 2017-02-20 Valery Alexeev

We study the moduli spaces of surface pairs $(X,D)$ admitting a log Calabi--Yau fibration $(X,D) \to C$. We develop a series of results on stable reduction and apply them to give an explicit description of the boundary of the KSBA…

Algebraic Geometry · Mathematics 2025-09-18 Giovanni Inchiostro , Roberto Svaldi , Junyan Zhao

Let $f: X \to Z$ be a fibration from a normal projective variety $X$ of dimension $n$ onto a normal curve $Z$ over a perfect field of characteristic $p>2$. Let $(X, B)$ be a dlt pair such that the induced pair on a general fibre is log…

Algebraic Geometry · Mathematics 2026-05-25 Marta Benozzo

In this note, using methods introduced by Hacon, McKernan and Xu, we study the accumulation points of volumes of varieties of log general type. First, we show that, if the set of boundary coefficients $\Lambda$ is DCC, closed under limits…

Algebraic Geometry · Mathematics 2020-04-22 Stefano Filipazzi

We show that in any $\mathbb{Q}$-Gorenstein flat family of klt singularities, normalized volumes can only jump down at countably many subvarieties. A quick consequence is that smooth points have the largest normalized volume among all klt…

Algebraic Geometry · Mathematics 2017-11-21 Yuchen Liu

We prove that for a locally stable family of klt singularities with constant local volume, the ideal sequences of the minimizing valuations for the normalized volume function form a family of ideals with flat cosupport, which induces a…

Algebraic Geometry · Mathematics 2025-10-14 Zhiyuan Chen

We establish the generalized canonical bundle formula for generalized lc-trivial fibrations with irrational coefficients over non-compact bases in the complex analytic setting, and we show that the discriminant b-divisor and moduli…

Algebraic Geometry · Mathematics 2026-05-05 Kenta Hashizume

In this paper, we present a general wall crossing theory for K-stability and K-moduli of log Fano pairs whose boundary divisors can be non-proportional to the anti-canonical divisor. Along the way, we prove that there are only finitely many…

Algebraic Geometry · Mathematics 2026-04-14 Yuchen Liu , Chuyu Zhou

We survey recent results on the boundedness of the moduli functor of stable pairs

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

In this paper we investigate the geometry of projective varieties polarised by ample and more generally nef and big Weil divisors. First we study birational boundedness of linear systems. We show that if $X$ is a projective variety of…

Algebraic Geometry · Mathematics 2022-09-20 Caucher Birkar

In this paper, we generalize the finiteness of models theorem in [BCHM06] to Kawamata log terminal pairs with fixed Kodaira dimension. As a consequence, we prove that a Kawamata log terminal pair with $\mathbb{R}-$boundary has a canonical…

Algebraic Geometry · Mathematics 2020-05-08 Junpeng Jiao

We construct log canonical pairs $(X,B)$ with $B$ a nonzero reduced divisor and $K_X+B$ ample that have the smallest known volume. We conjecture that our examples have the smallest volume in each dimension. The conjecture is true in…

Algebraic Geometry · Mathematics 2026-05-26 Louis Esser , Burt Totaro

Logarithmic Hilbert and Quot spaces are generalizations of their traditional versions adapted to study pairs and degenerations. The logarithmic Quot spaces of $(X,D)$ parameterize "algebraically transverse" (logarithmically flat) quotient…

Algebraic Geometry · Mathematics 2025-08-12 Patrick Kennedy-Hunt , Dhruv Ranganathan

Let $f:X\to U$ be a projective morphism of normal varieties and $(X,\Delta)$ a dlt pair. We prove that if there is an open set $U^0\subset U$, such that $(X,\Delta)\times_U U^0$ has a good minimal model over $U^0$ and the images of all the…

Algebraic Geometry · Mathematics 2012-06-29 Christopher D. Hacon , Chenyang Xu