English
Related papers

Related papers: Log canonical pairs with boundaries containing amp…

200 papers

Let $(X,\Delta)$ be a projective klt pair, and $f:X\to Y$ a fibration to a smooth projective variety $Y$ with strictly nef relative anti-log canonical divisor $-(K_{X/Y}+\Delta)$. We prove that $f$ is a locally constant fibration with…

Algebraic Geometry · Mathematics 2024-08-06 Jie Liu , Wenhao Ou , Juanyong Wang , Xiaokui Yang , Guolei Zhong

We show the termination of any log-minimal model program for a pair $(X,\Delta)$ of a symplectic manifold $X$ and an effective $\mathbb R$-divisor $\Delta$.

Algebraic Geometry · Mathematics 2014-05-23 Christian Lehn , Gianluca Pacienza

We discuss the cone theorem for quasi-log schemes and the Mori hyperbolicity. In particular, we establish that the log canonical divisor of a Mori hyperbolic projective normal pair is nef if it is nef when restricted to the non-lc locus.…

Algebraic Geometry · Mathematics 2022-12-27 Osamu Fujino

Given a log canonical pair $(X, \Delta)$, we show that $K_X+\Delta$ is nef assuming there is no non-constant map from the affine line with values in the open strata of the stratification induced by the non-klt locus of $(X, \Delta)$. This…

Algebraic Geometry · Mathematics 2021-10-12 Roberto Svaldi

Let X be a complex projective variety and D a reduced divisor on X. Under a natural minimal condition on the singularities of the pair (X, D), which includes the case of smooth X with simple normal crossing D, we ask for geometric criteria…

Algebraic Geometry · Mathematics 2018-09-24 Steven S. Y. Lu , De-Qi Zhang

Let $(X,\Delta)$ be a smooth complex projective simple normal crossing pair of dimension $n\geq 3$ endowed with an everywhere nondegenerate logarithmic conformal tensor. If $K_X+\Delta$ is not nef, then precisely one of the following…

Algebraic Geometry · Mathematics 2026-04-20 Maurício Corrêa , Alex Massarenti

Let $(X,\Delta)$ be a log canonical pair over $\mathbb{C}$ with $X$ a normal projective variety, $\Delta$ an effective $\mathbb{Q}$-divisor, and $K_X+\Delta$ nef. We give a non-vanishing criterion for $K_X+\Delta$ in dimension $n$ with $X$…

Algebraic Geometry · Mathematics 2019-08-02 Fanjun Meng

Let $(P\in X,\Delta)$ be a three dimensional log canonical pair such that $\Delta$ has only standard coefficients and $P$ is a center of log canonical singularities for $(X,\Delta)$. Then we get an effective bound of the indices of these…

Algebraic Geometry · Mathematics 2007-05-23 Osamu Fujino

In this paper, we give a characterization of Fano type varieties in terms of the asymptotic base loci of $-(K_X+\Delta)$. We also show that for a potentially lc pair $(X,\Delta)$, if no plc centers are contained in the augmented base locus…

Algebraic Geometry · Mathematics 2025-06-17 Sung Rak Choi , Sungwook Jang , Dae-Won Lee

In this article we show that the Log Minimal Model Program holds for $\mathbb{Q}$-factorial lc pair $(X,\Delta)$ with $X$ being a compact K\"ahler $3$-fold having only klt singularities.

Algebraic Geometry · Mathematics 2023-06-14 Roktim Mascharak

One of the central aims of the Minimal Model Program is to show that a projective log canonical pair $(X,\Delta)$ with $K_X+\Delta$ pseudoeffective has a good model, i.e.\ a minimal model $(Y,\Delta_Y)$ such that $K_Y+\Delta_Y$ is…

Algebraic Geometry · Mathematics 2025-08-22 Vladimir Lazić

Semi-log canonical varieties are a higher-dimensional analogue of stable curves. They are the varieties appearing as the boundary $\Delta$ of a log canonical pair $(X,\Delta)$, and also appear as limits of canonically polarized varieties in…

Algebraic Geometry · Mathematics 2019-08-14 Morgan V Brown

We prove that one can run the log minimal model program for log canonical $3$-fold pairs in characteristic $p>5$. In particular we prove the Cone Theorem, Contraction Theorem, the existence of flips and the existence of log minimal models…

Algebraic Geometry · Mathematics 2017-01-11 Joe Waldron

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

Let $(X, \Delta)$ be a projective log canonical Calabi-Yau pair and $L$ an ample $\mathbb{Q}$-line bundle on $X$, we show that there is a correspondence between lc places of $(X, \Delta)$ and weakly special test configurations of $(X,…

Algebraic Geometry · Mathematics 2025-01-07 Guodu Chen , Chuyu Zhou

Suppose that $X$ is a projective variety over an algebraically closed field of characteristic $p > 0$. Further suppose that $L$ is an ample (or more generally in some sense positive) divisor. We study a natural linear system in $|K_X + L|$.…

Algebraic Geometry · Mathematics 2012-08-24 Karl Schwede

For lc algebraically integrable foliations on klt varieties, we prove the base-point-freeness theorem, the contraction theorem, and the existence of flips. The first result resolves a conjecture of Cascini and Spicer, while the latter two…

Algebraic Geometry · Mathematics 2025-06-09 Jihao Liu , Fanjun Meng , Lingyao Xie

We will prove the following results for $3$-fold pairs $(X,B)$ over an algebraically closed field $k$ of characteristic $p>5$: log flips exist for $\Q$-factorial dlt pairs $(X,B)$; log minimal models exist for projective klt pairs $(X,B)$…

Algebraic Geometry · Mathematics 2014-10-17 Caucher Birkar

There are two main examples where a version of the Minimal Model Program can, at least conjecturally, be performed successfully: the first is the classical MMP associated to the canonical divisor, and the other is Mori Dream Spaces. In this…

Algebraic Geometry · Mathematics 2021-05-18 Anne-Sophie Kaloghiros , Alex Küronya , Vladimir Lazić

We prove the finiteness of log pluricanonical representations for projective log canonical pairs with semi-ample log canonical divisor. As a corollary, we obtain that the log canonical divisor of a projective semi log canonical pair is…

Algebraic Geometry · Mathematics 2012-04-10 Osamu Fujino , Yoshinori Gongyo