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Related papers: Potentially non-klt locus and its applications

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Let $X^n \subset P^N$ be a nonsingular, nondegenerate projective variety of dimension $n$ and codimension $N-n \ge 2$. Let $|C_X|$ be the linear system determined by the double-point divisor obtained by generically projecting $X$ to a…

alg-geom · Mathematics 2008-02-03 Bo Ilic

Let $X$ be a very general hypersurface of degree $d$ in the projective $(n+1)$-space with $n \ge 3$, and $f: X \to Y$ a non-birational surjective morphism to a normal projective variety $Y$. We first prove that $Y$ is a klt Fano variety if…

Algebraic Geometry · Mathematics 2025-08-26 Yongnam Lee , Yujie Luo , De-Qi Zhang

We classify Fano 3-folds with canonical Gorenstein singularities whose anticanonical linear system has no base points but does not give an embedding, and we classify anticanonically embedded Fano 3-folds with canonical Gorenstein…

Algebraic Geometry · Mathematics 2007-05-23 Ivan Cheltsov , Constantin Shramov , Victor Przyjalkowski

We study the Iitaka-Kodaira dimension of nef relative anti-canonical divisors. As a consequence, we prove that given a complex projective variety with klt singularities, if the anti-canonical divisor is nef, then the dimension of a general…

Algebraic Geometry · Mathematics 2019-07-10 Sho Ejiri , Yoshinori Gongyo

In this paper, we study the relative anti-canonical divisor $-K_{X/Y}$ of an algebraic fiber space $\phi: X \to Y$, and we reveal relations among positivity conditions of $-K_{X/Y}$, certain flatness of direct image sheaves, and variants of…

Algebraic Geometry · Mathematics 2020-05-12 Sho Ejiri , Masataka Iwai , Shin-ichi Matsumura

We construct a supercategory that can be seen as a skew version of (thickened) KLR algebras for the type $A$ quiver. We use our supercategory to construct homological invariants of tangles and show that for every link our invariant gives a…

Quantum Algebra · Mathematics 2020-12-09 Pedro Vaz

Let X be a compact K\"ahler manifold such that the anticanonical bundle $-K_X$ is nef. A classical conjecture claims that the Albanese map is submersive. We prove this conjecture if the general fibre is a weak Fano manifold. If X is…

Algebraic Geometry · Mathematics 2017-10-30 Junyan Cao , Andreas Höring

We prove that termination of lower dimensional flips for generalized klt pairs implies termination of flips for log canonical generalized pairs with a weak Zariski decomposition. Moreover, we prove that the existence of weak Zariski…

Algebraic Geometry · Mathematics 2020-03-26 Christopher D. Hacon , Joaquín Moraga

In this short note, we give an alternative proof of the semipositivity of the Chow-Mumford line bundle for families of K-semistable log-Fano pairs, and of the nefness threeshold for the log-anti-canonical line bundle on families of K-stable…

Algebraic Geometry · Mathematics 2023-07-14 Giulio Codogni , Zsolt Patakfalvi

We prove that a pair (X, D) with X Fano and D a smooth anti-canonical divisor is K-unstable for negative angles, and K-semistable for zero angle.

Differential Geometry · Mathematics 2013-01-16 Song Sun

It is known that projective minimal models satisfy the celebrated Miyaoka-Yau inequalities. In this article, we extend these inequalities to the set of all smooth, projective and non-uniruled varieties.

Algebraic Geometry · Mathematics 2022-08-03 Erwan Rousseau , Behrouz Taji

In this paper we study the functional central limit theorem for stationary Markov chains with self-adjoint operator and general state space. We investigate the case when the variance of the partial sum is not asymptotically linear in n; and…

Probability · Mathematics 2013-05-10 Martial Longla , Costel Peligrad , Magda Peligrad

We prove that the target space of an extremal Fano contraction from a log canonical pair has only log canonical singularities. We also treat some related topics, for example, the finite generation of canonical rings for compact K\"ahler…

Algebraic Geometry · Mathematics 2014-06-26 Osamu Fujino

The 'moduli continuity method' permits an explicit algebraisation of the Gromov-Hausdorff compactification of K\"ahler-Einstein metrics on Fano manifolds in some fundamental examples. In this paper, we apply such method in the 'log setting'…

Algebraic Geometry · Mathematics 2020-11-11 Patricio Gallardo , Jesus Martinez-Garcia , Cristiano Spotti

A determination of the fixed components, base points and irregularity is made for arbitrary numerically effective divisors on any smooth projective rational surface having an effective anticanonical divisor. All of the results are proven…

alg-geom · Mathematics 2009-09-25 Brian Harbourne

In this article, we introduce a new approach to show the existence and smoothing of simple normal crossing varieties in a given projective space. Our approach relates the above to the existence of nowhere reduced schemes called ribbons and…

Algebraic Geometry · Mathematics 2024-03-08 Purnaprajna Bangere , Francisco Javier Gallego , Jayan Mukherjee

The objective of the present article is to construct the first examples of (non-trivial) non-commutative projective Calabi-Yau schemes in the sense of Artin and Zhang.

Algebraic Geometry · Mathematics 2014-10-21 Atsushi Kanazawa

The aim of this paper is to study geometric properties of non-degenerate smooth projective varieties of small degree from a birational point of view. First, using the positivity property of double point divisors and the adjunction mappings,…

Algebraic Geometry · Mathematics 2019-02-20 Sijong Kwak , Jinhyung Park

We present a fixed point theorem for a class of (potentially) non-monotonic functions over specially structured complete lattices. The theorem has as a special case the Knaster-Tarski fixed point theorem when restricted to the case of…

Logic in Computer Science · Computer Science 2015-02-10 Zoltán Ésik , Panos Rondogiannis

This paper contains three related groupings of results. First, we consider a new notion of an admissible skein module of a surface associated to an ideal in a (non-semisimple) pivotal category. Second, we introduce the notion of a chromatic…

Quantum Algebra · Mathematics 2024-04-18 Francesco Costantino , Nathan Geer , Bertrand Patureau-Mirand , Alexis Virelizier