English
Related papers

Related papers: On the volume of K-semistable Fano manifolds

200 papers

We show that any $n$-dimensional Fano manifold $X$ admitting K\"ahler-Einstein metrics satisfies that the anti-canonical volume is less than or equal to the value $(n+1)^n$. Moreover, the equality holds if and only if $X$ is isomorphic to…

Algebraic Geometry · Mathematics 2015-08-20 Kento Fujita

We show that the anti-canonical volume of an $n$-dimensional K\"ahler-Einstein $\mathbb{Q}$-Fano variety is bounded from above by certain invariants of the local singularities, namely $\mathrm{lct}^n\cdot\mathrm{mult}$ for ideals and the…

Algebraic Geometry · Mathematics 2019-02-20 Yuchen Liu

For a real number $0<\epsilon<1/3$, we show that the anti-canonical volume of an $\epsilon$-klt Fano $3$-fold is at most $3200/\epsilon^4$ and the order $O(1/\epsilon^4)$ is sharp.

Algebraic Geometry · Mathematics 2024-11-20 Chen Jiang , Yu Zou

It was proved by J. A. Chen and M. Chen that a terminal Fano $3$-fold $X$ satisfies $(-K_X)^3\geq \frac{1}{330}$. We show that a non-rational $\mathbb{Q}$-factorial terminal Fano $3$-fold $X$ with $\rho(X)=1$ and $(-K_X)^3=\frac{1}{330}$ is…

Algebraic Geometry · Mathematics 2025-05-08 Chen Jiang

We show that the anti-canonical volume of a canonical weak Fano $3$-fold is at most $72$. This upper bound is optimal.

Algebraic Geometry · Mathematics 2025-10-09 Chen Jiang , Tianqi Zhang , Yu Zou

We show that for a weak $\mathbb{Q}$-Fano threefold $X$ of Picard rank two ($\mathbb{Q}$-factorial with at worst terminal singularities), the anticanonical volume satisfies $-K_X^3\leq72$ except in one case, and the equality holds only if…

Algebraic Geometry · Mathematics 2025-01-23 Ching-Jui Lai

Let $(X,\Delta)$ be an $n$-dimensional $\epsilon$-klt log $\QQ$-Fano pair. We give an upper bound for the volume ${\rm Vol}(-(K_X+\Delta))=(-(K_X+\Delta))^n$ when $n=2$ or $n=3$ and $X$ is {$\QQ$-factorial} of $\rho(X)=1$. This bound is…

Algebraic Geometry · Mathematics 2012-04-13 Ching-Jui Lai

We find an explicit upper bound for the anticanonical volume of Fano 4-folds with canonical singularities.

Algebraic Geometry · Mathematics 2022-09-20 Caucher Birkar

We show that the anti-canonical volume of a canonical weak $\mathbb{Q}$-Fano $3$-fold is at most $324$.

Algebraic Geometry · Mathematics 2024-05-28 Chen Jiang , Yu Zou

We demonstrate the generic invariance of the Fano type property in cases where the volumes of anti-canonical divisors of Fano type fibers are a constant over a Zariski-dense subset, or the Fano type fibers are dimension $2$. Additionally,…

Algebraic Geometry · Mathematics 2025-09-24 Donghyeon Kim

We construct klt projective varieties with ample canonical class and the smallest known volume. We also find exceptional klt Fano varieties with the smallest known anticanonical volume. We conjecture that our examples have the smallest…

Algebraic Geometry · Mathematics 2022-11-03 Burt Totaro

We give an upper bound on the volume vol(P*) of a polytope P* dual to a d-dimensional lattice polytope P with exactly one interior lattice point, in each dimension d. This bound, expressed in terms of the Sylvester sequence, is sharp, and…

Combinatorics · Mathematics 2016-11-09 Gabriele Balletti , Alexander M. Kasprzyk , Benjamin Nill

Fix two positive integers $d\geq3$ and $q$. We give an upper bound for anti-canonical volumes of $d$-dimensional $\frac{1}{q}$-lc toric Fano varieties, which corresponds to an upper bound for the dual normalized volumes of the associated…

Algebraic Geometry · Mathematics 2024-11-26 Yu Zou

Let $X$ be a Fano manifold of Picard number one. We establish a lower bound for the second Chern class of $X$ in terms of its index and degree. As an application, if $Y$ is a $n$-dimensional Fano manifold with $-K_Y=(n-3)H$ for some ample…

Algebraic Geometry · Mathematics 2018-05-29 Jie Liu

Let $X$ be a terminal weak $\bQ$-Fano threefold. We prove that $P_{-6}(X)>0$ and $P_{-8}(X)>1$. We also prove that the anti-canonical volume has a universal lower bound $-K_X^3 \geq 1/330$. This lower bound is optimal.

Algebraic Geometry · Mathematics 2009-11-10 Jungkai Alfred Chen , Meng Chen

We conjecture that for every dimension n not equal 3 there exists a noncompact hyperbolic n-manifold whose volume is smaller than the volume of any compact hyperbolic n-manifold. For dimensions n at most 4 and n=6 this conjecture follows…

Metric Geometry · Mathematics 2015-04-09 Mikhail Belolipetsky , Vincent Emery

We consider some families of smooth Fano hypersurfaces $X_{n+2}$ in ${\bf P}^{n+2} \times {\bf P}^3$ given by a homogeneous polynomial of bidegree $(1,3)$. For these varieties we obtain lower bounds for the number of $F$-rational points of…

alg-geom · Mathematics 2008-02-03 Victor V. Batyrev , Yuri Tschinkel

We prove that a Fano variety (with arbitrary singularities) of dimension $n$ in positive characteristic is isomorphic to $\mathbb{P}^n$ if the Seshadri constant of the anti-canonical divisor at some smooth point is greater than $n$ and…

Algebraic Geometry · Mathematics 2020-08-06 Ziquan Zhuang

In our previous work we conjectured - inspired by an algebro-geometric result of Fujita - that the height of an arithmetic Fano variety X of relative dimension $n$ is maximal when X is the projective space $\mathbb{P}^n_{\mathbb{Z}}$ over…

Algebraic Geometry · Mathematics 2024-03-05 Rolf Andreasson , Robert J. Berman

Given $\epsilon>0$, we show that over an algebraically closed field of characteristic $p>5$, the anticanonical volume of a Fano threefold $X$ (with arbitrary singularities) whose anticanonical divisor has Seshadri constant…

Algebraic Geometry · Mathematics 2020-08-05 Ziquan Zhuang
‹ Prev 1 2 3 10 Next ›