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Related papers: On normal Seshadri stratifications

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We introduce the notion of a Seshadri stratification on an embedded projective variety. Such a structure enables us to construct a Newton-Okounkov simplicial complex and a flat degeneration of the projective variety into a union of toric…

Algebraic Geometry · Mathematics 2024-04-10 Rocco Chirivì , Xin Fang , Peter Littelmann

We apply the theory of Seshadri stratifications to embedded toric varieties $X_P\subseteq \mathbb P(V)$ associated with a normal lattice polytope $P$. The approach presented here is purely combinatorial and completely independent of…

Algebraic Geometry · Mathematics 2025-05-06 Rocco Chirivì , Martina Costa Cesari , Xin Fang , Peter Littelmann

The theory of Seshadri stratifications has been developed by the authors with the intention to build up a new geometric approach towards a standard monomial theory for embedded projective varieties with certain nice properties. In this…

Algebraic Geometry · Mathematics 2022-08-12 Rocco Chirivì , Xin Fang , Peter Littelmann

A standard monomial theory for Schubert varieties is constructed exploiting (1) the geometry of the Seshadri stratifications of Schubert varieties by their Schubert subvarieties and (2) the combinatorial LS-path character formula for…

Algebraic Geometry · Mathematics 2024-04-10 Rocco Chirivì , Xin Fang , Peter Littelmann

It is shown that a complex normal projective variety has non-positive Kodaira dimension if it admits a non-isomorphic quasi-polarized endomorphism. The geometric structure of the variety is described by methods of equivariant lifting and…

Algebraic Geometry · Mathematics 2018-09-24 Noboru Nakayama , De-Qi Zhang

We provide an algebraic-geometrical interpretation of the classical semistandard Young-tableaux via the notion of Seshadri stratifications. The columns appearing in such a tableau correspond to vanishing multiplicities of certain rational…

Algebraic Geometry · Mathematics 2024-08-30 Henrik Müller

Let $X$ be a normal projective variety admitting a polarized or int-amplified endomorphism $f$. We list up characteristic properties of such an endomorphism and classify such a variety from the aspects of its singularity, anti-canonical…

Algebraic Geometry · Mathematics 2020-06-11 Sheng Meng , De-Qi Zhang

We give a method to estimate Seshadri constants on toric varieties at any point. By using the estimations and toric degenerations, we can obtain some new computations or estimations of Seshadri constants on non-toric varieties. In…

Algebraic Geometry · Mathematics 2013-02-01 Atsushi Ito

Our primary result is that a demi-normal quasi-projective variety can be embedded in a demi-normal projective variety. Recall that a demi-normal variety $X$ is a variety with properties $S_2$, $G_1$, and seminormality. Equivalently, $X$ has…

Algebraic Geometry · Mathematics 2014-11-11 Jeremy Berquist

We introduce the Seshadri region of a subvariety, a convex region packaging the classical Seshadri constants with respect to every line bundle simultaneously. We develop the theory of Seshadri regions as a measure of positivity along…

Algebraic Geometry · Mathematics 2025-12-08 Juliette Bruce , Lauren Cranton Heller , Mahrud Sayrafi , Alexandra Seceleanu

Using the language of Seshadri stratifications we develop a geometrical interpretation of Lakshmibai-Seshadri-tableaux and their associated standard monomial bases. These tableaux are a generalization of Young-tableaux and…

Algebraic Geometry · Mathematics 2024-09-19 Henrik Müller

Let $X$ be a normal projective variety and $f:X\to X$ a non-isomorphic polarized endomorphism. We give two characterizations for $X$ to be a toric variety. First we show that if $X$ is $\mathbb{Q}$-factorial and $G$-almost homogeneous for…

Algebraic Geometry · Mathematics 2019-08-05 Sheng Meng , De-Qi Zhang

In "Seshadri fibrations of algebraic surfaces" [arXiv:0709.2592v1] we showed that if the multiple point Seshadri constants of an ample line bundle on a smooth projective surface in very general points satisfy certain inequality then the…

Algebraic Geometry · Mathematics 2008-06-10 Wioletta Syzdek , Tomasz Szemberg

We consider the set of forms of a toric variety over an arbitrary field: those varieties which become isomorphic to a toric variety after base field extension. In contrast to most previous work, we also consider arbitrary isomorphisms…

Algebraic Geometry · Mathematics 2016-10-04 Alexander Duncan

By analogy with algebraic geometry, we define a category of non-linear sheaves (quasi-coherent homotopy-sheaves of topological spaces) on projective toric varieties and prove a splitting result for its algebraic K-theory, generalising…

K-Theory and Homology · Mathematics 2010-07-30 Thomas Huettemann

We extend the classical notion of standardly stratified $k$-algebra (stated for finite dimensional $k$-algebras) to the more general class of rings, possibly without $1,$ with enough idempotents. We show that many of the fundamental…

Rings and Algebras · Mathematics 2020-09-03 O. Mendoza , M. Ortíz , C. Sáenz , V. Santiago

We compute Seshadri constants of a torus equivariant nef vector bundle on a projective space satisfying certain conditions. As an application, we compute Seshadri constants of tangent bundles on projective spaces. We also consider…

Algebraic Geometry · Mathematics 2021-05-11 Jyoti Dasgupta , Bivas Khan , Aditya Subramaniam

We provide a characterization of homogeneous spaces under a reductive group scheme such that the geometric stabilizers are maximal tori. The quasi-split case over a semilocal base is of special interest and permits to answer a question…

Algebraic Geometry · Mathematics 2025-02-04 Philippe Gille , Ting-Yu Lee

We provide a construction of examples of semistable degeneration via toric geometry. The applications include a higher dimensional generalization of classical degeneration of K3 surface into 4 rational components, an algebraic geometric…

Algebraic Geometry · Mathematics 2007-05-23 Shengda Hu

Given a smooth projective toric variety $X_\Sigma$ of complex dimension $n$, Fang-Liu-Treumann-Zaslow \cite{FLTZ} showed that there is a quasi-embedding of the differential graded (dg) derived category of coherent sheaves $Coh(X_\Sigma)$…

Algebraic Geometry · Mathematics 2017-01-04 Peng Zhou
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