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相关论文: A note on a stability result for the Fano plane

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In this paper we consider spectral extremal problems for hypergraphs. We give two general criteria under which such results may be deduced from `strong stability' forms of the corresponding (pure) extremal results. These results hold for…

组合数学 · 数学 2014-03-07 Peter Keevash , John Lenz , Dhruv Mubayi

We develop a general approach to prove K-stability of Fano varieties. The new theory is used to (a) prove the existence of K\"ahler-Einstein metrics on all smooth Fano hypersurfaces of Fano index two, (b) to compute the stability thresholds…

代数几何 · 数学 2022-06-15 Hamid Abban , Ziquan Zhuang

Confirming a conjecture of Vera T. S\'os in a very strong sense, we give a complete solution to Tur\'an's hypergraph problem for the Fano plane. That is we prove for $n\ge 8$ that among all $3$-uniform hypergraphs on $n$ vertices not…

组合数学 · 数学 2020-03-24 Louis Bellmann , Christian Reiher

We prove a criterion for K-stability of a $\mathbb{Q}$-Fano spherical variety with respect to equivariant special test configurations, in terms of its moment polytope and some combinatorial data associated to the open orbit. Combined with…

代数几何 · 数学 2020-09-16 Thibaut Delcroix

We provide a sufficient condition for polarisations of Fano varieties to be K-stable in terms of Tian's alpha invariant, which uses the log canonical threshold to measure singularities of divisors in the linear system associated to the…

代数几何 · 数学 2016-04-21 Ruadhaí Dervan

A classical object in hypergraph Tur\'{a}n theory is the Fano plane $\mathbb{F}$, the unique linear $3$-graph on seven vertices with seven edges. The Tur\'{a}n density and exact Tur\'{a}n number of $\mathbb{F}$, first proposed as a problem…

组合数学 · 数学 2025-07-17 Jianfeng Hou , Xizhi Liu , Yixiao Zhang

Let X be a Fano manifold. G.Tian proves that if X admits a Kaehler-Einstein metric, then it satisfies two different stability conditions: one involving the Futaki invariant of a special degeneration of X, the other Hilbert-Mumford-stability…

代数几何 · 数学 2007-05-23 Thomas Rudolf Bauer

Given a sequence $\mathbf{k} := (k_1,\ldots,k_s)$ of natural numbers and a graph $G$, let $F(G;\mathbf{k})$ denote the number of colourings of the edges of $G$ with colours $1,\dots,s$ such that, for every $c \in \{1,\dots,s\}$, the edges…

组合数学 · 数学 2023-05-09 Oleg Pikhurko , Katherine Staden

We give a lower bound of the $\delta$-invariants of ample line bundles in terms of Seshadri constants. As applications, we prove the uniform K-stability of infinitely many families of Fano hypersurfaces of arbitrarily large index, as well…

代数几何 · 数学 2022-04-28 Hamid Abban , Ziquan Zhuang

The classical stability theorem of Erd\H{o}s and Simonovits states that, for any fixed graph with chromatic number $k+1 \ge 3$, the following holds: every $n$-vertex graph that is $H$-free and has within $o(n^2)$ of the maximal possible…

组合数学 · 数学 2018-10-05 Alexander Roberts , Alex Scott

The stability method is very useful for obtaining exact solutions of many extremal graph problems. Its key step is to establish the stability property which, roughly speaking, states that any two almost optimal graphs of the same order $n$…

组合数学 · 数学 2010-07-30 Oleg Pikhurko

We settle the problem of K-stability of quasi-smooth Fano 3-fold hypersurfaces with Fano index 1 by providing lower bounds for their delta invariants. We use the method introduced by Abban and Zhuang for computing lower bounds of delta…

代数几何 · 数学 2026-05-27 Livia Campo , Takuzo Okada

We consider the Tur\'an-type problem of bounding the size of a set $M \subseteq \mathbb{F}_2^n$ that does not contain a linear copy of a given fixed set $N \subseteq \mathbb{F}_2^k$, where $n$ is large compared to $k$. An Erd\H{o}s-Stone…

组合数学 · 数学 2017-10-12 Hong Liu , Sammy Luo , Peter Nelson , Kazuhiro Nomoto

It's well-known that adding a general boundary would create K-stability. As an application, we reprove product theorem for delta invariants of Fano varieties.

代数几何 · 数学 2025-01-06 Chuyu Zhou

Erd\H{o}s-Stone Theorem is a well-known result in extremal graph theory which determines the asymptotic behaviour of maximum number of edges in an $n$-vertex $H$-free graph. In 2009, Nikiforov gave a spectral version of Erd\H{o}s-Stone…

组合数学 · 数学 2024-03-11 Chunmeng Liu , Jiang Zhou , Changjiang Bu

In 1987, the $\alpha$-invariant theorem gave a fundamental criterion for existence of Kahler-Einstein metrics on smooth Fano manifolds. In 2012, Odaka-Sano extended the framework to $\mathbb{Q}$-Fano varieties in terms of K-stability, and…

微分几何 · 数学 2025-01-31 Chenzi Jin , Yanir A. Rubinstein , Gang Tian

We prove some criteria for uniform K-stability of log Fano pairs. In particular, we show that uniform K-stability is equivalent to $\beta$-invariant having a positive lower bound. Then we study the relation between optimal destabilization…

代数几何 · 数学 2025-01-06 Chuyu Zhou , Ziquan Zhuang

Extending the work of Liu--Mubayi--Reiher~\cite{LMR23unif} on hypergraph Tur\'{a}n problems, we introduce the notion of vertex-extendability for general extremal problems on hypergraphs and develop an axiomatized framework for proving…

组合数学 · 数学 2024-06-11 Wanfang Chen , Xizhi Liu

In this note, we use recent advances concerning the K-stability of $\mathbb{Q}$-Fano varieties to provide settings for which Vojta's conjecture holds.

代数几何 · 数学 2024-01-04 Jackson S. Morrow , Yueqiao Wu

In this paper, we consider the Kirchhoff plate equation with delay terms on the boundary control are added (see system \eqref{p5-2.1} below). we give some instability examples of system \eqref{p5-2.1} for some choices of delays. Finally, we…

偏微分方程分析 · 数学 2022-11-21 Mohammad Akil , Haidar Badawi , Mohamed Balegh , Zayd Hajjej
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