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Related papers: K-semistability is equivariant volume minimization

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We show that being a general fibre of a Mori fibre space is a rather restrictive condition for a Fano variety. More specifically, we obtain two criteria (one sufficient and one necessary) for a Q-factorial Fano variety with terminal…

Algebraic Geometry · Mathematics 2016-06-09 Giulio Codogni , Andrea Fanelli , Roberto Svaldi , Luca Tasin

We use Drinfeld style generators and relations to define an algebra $\mathfrak{U}_n$ which is a ``$q=0$'' version of the affine quantum group of $\mathfrak{gl}_n.$ We then use the convolution product on the equivariant $K$-theory of…

Representation Theory · Mathematics 2025-05-28 Sergey Arkhipov , Mikhail Mazin

Suppose that f is a dominant morphism from a k-variety X to a k-variety Y, where k is a field of characteristic 0 and v is a valuation of the function field k(X). We allow v to be an arbitary valuation, so it may not be discrete. We prove…

Algebraic Geometry · Mathematics 2007-05-23 Steven Dale Cutkosky

Using the description of the category of quasi-coherent sheaves on a root stack given in the paper of N. Borne and A. Vistoli, we study the G-theory of root stacks via localisation methods. We apply our results to the study of equivariant…

Algebraic Geometry · Mathematics 2019-08-14 A. Dhillon , I. Kobyzev

We introduce a concept of minimality for Fano polygons. We show that, up to mutation, there are only finitely many Fano polygons with given singularity content, and give an algorithm to determine the mutation-equivalence classes of such…

Algebraic Geometry · Mathematics 2022-10-28 Alexander Kasprzyk , Benjamin Nill , Thomas Prince

In this paper, a semi-discrete spatial finite volume (FV) method is proposed and analyzed for approximating solutions of anomalous subdiffusion equations involving a temporal fractional derivative of order $\alpha \in (0,1)$ in a…

Numerical Analysis · Mathematics 2015-10-27 Samir Karaa , Kassem Mustapha , Amiya K. Pani

The quantum lens spaces form a natural and well-studied class of noncommutative spaces which can be subjected to classification using algebraic invariants by drawing on the fully developed classification theory of unital graph…

Operator Algebras · Mathematics 2025-01-30 Søren Eilers , Sophie Emma Zegers

We find Fano threefolds $X$ admitting K\"ahler-Ricci solitons (KRS) with non-trivial moduli, which are $\mathbb{T}$-varieties of complexity two. More precisely, we show that the weighted K-stability of $(X,\xi_0)$ (where $\xi_0$ is the…

Algebraic Geometry · Mathematics 2025-08-01 Minghao Miao , Linsheng Wang

Let F:X->B be a morphism of varieties in characteristic zero. The problem of semistable reduction of F was stated as a problem in the combinatorics of polyhedral complexes by Abramovich and Karu (alg-geom/9707012). In this paper we solve…

alg-geom · Mathematics 2007-05-23 Kalle Karu

We prove that the K-moduli space of cubic fourfolds is identical to their GIT moduli space. More precisely, the K-(semi/poly)stability of cubic fourfolds coincide to the corresponding GIT stabilities, which was studied in detail by Laza. In…

Algebraic Geometry · Mathematics 2022-01-11 Yuchen Liu

For any log Fano pair with a torus action, we associate a computable invariant to it, such that the pair is (weighted) K-polystable if and only if this invariant is greater than one. As an application, we present examples of Fano varieties…

Algebraic Geometry · Mathematics 2025-10-14 Linsheng Wang

We classify group schemes in terms of their Cartier modules. We also prove the equivalence of different definitions of the tangent space and the dimension for these group schemes; in particular, the minimal dimension of a formal group law…

Algebraic Geometry · Mathematics 2007-05-23 M. V. Bondarko

We introduce a norm on the space of test configurations, which we call the minimum norm. We conjecture that uniform K-stability with respect to this norm is equivalent to the existence of a constant scalar curvature K\"ahler metric. This…

Differential Geometry · Mathematics 2015-06-22 Ruadhaí Dervan

We prove some fundamental results like localization, excision, Nisnevich descent and the Mayer-Vietoris property for equivariant regular blow-up for the equivariant K-theory of schemes with an affine group scheme action. We also show that…

Algebraic Geometry · Mathematics 2017-08-03 Amalendu Krishna , Charanya Ravi

We prove an embedded local uniformization theroem for a valuation centered on a point of a quasi-excellent scheme of characteristic zero. The proof reduces to valuations of rank 1 and consists in desingularizing the ideal formed by the…

Algebraic Geometry · Mathematics 2013-11-15 Jean-Christophe San Saturnino

Let k_0 be a field of characteristic 0, and let k be a fixed algebraic closure of k_0. Let G be an algebraic k-group, and let Y be a G-variety over k. Let G_0 be a k_0 -model (k_0 -form) of G. We ask whether Y admits a G_0 -equivariant k_0…

Group Theory · Mathematics 2018-05-15 Mikhail Borovoi

We study the semistability of quiver representations from an algorithmic perspective. We present efficient algorithms for several fundamental computational problems on the semistability of quiver representations: deciding the semistability…

Optimization and Control · Mathematics 2025-05-13 Yuni Iwamasa , Taihei Oki , Tasuku Soma

We give a purely algebro-geometric proof that if the alpha-invariant of a Q-Fano variety X is greater than dim X/(dim X+1), then (X,O(-K_X)) is K-stable. The key of our proof is a relation among the Seshadri constants, the alpha-invariant…

Algebraic Geometry · Mathematics 2012-08-10 Yuji Odaka , Yuji Sano

We show that $\mathbb{Q}$-Fano varieties of fixed dimension with anti-canonical degrees and alpha-invariants bounded from below form a bounded family. As a corollary, K-semistable $\mathbb{Q}$-Fano varieties of fixed dimension with…

Algebraic Geometry · Mathematics 2021-01-22 Chen Jiang

The $k$-means method is an iterative clustering algorithm which associates each observation with one of $k$ clusters. It traditionally employs cluster centers in the same space as the observed data. By relaxing this requirement, it is…

Statistics Theory · Mathematics 2015-04-06 Matthew Thorpe , Florian Theil , Adam M. Johansen , Neil Cade