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The Nash problem on arc families is affirmatively answered for a toric variety by Ishii and Kollar's paper which also shows the negative answer for general case. The Nash problem is one of questions about the relation between arc families…

Algebraic Geometry · Mathematics 2007-05-23 Shihoko Ishii

This paper gives a map from the set of families of arcs on a variety to the set of valuations on the rational function field of the variety We characterize a family of arcs which corresponds to a divisorial valuation by this map. We can see…

Algebraic Geometry · Mathematics 2007-05-23 Shihoko Ishii

We study Nash valuations and essential valuations of terminal threefolds of type $cA/r$. If $r=1$ or the given threefold is $\mathbb Q$-factorial, then all the Nash valuations and essential valuations can be completely described. We…

Algebraic Geometry · Mathematics 2019-07-16 Hsin-Ku Chen

Let X be an algebraic variety of characteristic zero. Terminal valuations are defined in the sense of the minimal model program, as those valuations given by the exceptional divisors on a minimal model over X. We prove that every terminal…

Algebraic Geometry · Mathematics 2016-12-15 Tommaso de Fernex , Roi Docampo

In this paper we describe the implementation that led to the counterexamples to the Nash blowup conjectures recently discovered by the authors. We also provide new examples of toric varieties with prescribed singularities that are not…

Algebraic Geometry · Mathematics 2025-11-25 Federico Castillo , Daniel Duarte , Maximiliano Leyton-Álvarez , Alvaro Liendo

We present a solution for Nash problem for stable toric varieties. We also introduce Nash problem for pairs and prove it for toric pairs.

Algebraic Geometry · Mathematics 2007-05-23 Peter Petrov

This paper shows the affirmative answer to the local Nash problem for a toric singularity and analytically pretoric singularity. As a corollary we obtain the affirmative answer to the local Nash problem for a quasi-ordinary singularity.

Algebraic Geometry · Mathematics 2007-05-23 Shihoko Ishii

We study Nash valuations on 3-fold terminal singularities, especially in type cAx/2. We find that, in type cAx/2, exceptional prime divisors computing the minimal discrepancy (which is 1/2 in this case) induce Nash valuations. We conjecture…

Algebraic Geometry · Mathematics 2026-02-26 Keng-Hung Steven Lin

We introduce a torsor-theoretic obstruction to equivariant unirationality and show that it is also sufficient for actions of finite groups on toric varieties arising from automorphisms of the torus.

Algebraic Geometry · Mathematics 2025-06-10 Andrew Kresch , Yuri Tschinkel

Nash proved that every irreducible component of the space of arcs through a singularity corresponds to an exceptional divisor that occurs on every resolution. He asked if the converse also holds: does every such exceptional divisor…

Algebraic Geometry · Mathematics 2007-05-23 Shihoko Ishii , János Kollár

It has been recently shown that the iteration of Nash modification on not necessarily normal toric varieties corresponds to a purely combinatorial algorithm on the generators of the semigroup associated to the toric variety. We will show…

Algebraic Geometry · Mathematics 2015-03-19 Daniel Duarte

This paper studies generalized Nash equilibrium problems that are given by rational functions. The optimization problems are not assumed to be convex. Rational expressions for Lagrange multipliers and feasible extensions of KKT points are…

Optimization and Control · Mathematics 2023-02-23 Jiawang Nie , Xindong Tang , Suhan Zhong

Variational relation problems allow a general approach for variational inequalities, equilibrium problems, optimization problems, variational inclusions. In this paper we consider a system of quasi-variational relations and determine some…

Optimization and Control · Mathematics 2013-06-04 Daniela Inoan

The paper is based on a talk. Complete exposition is given in "Equivariant Hirzebruch class for singular varieties". Starting from the classical theory we describe Hirzebruch class and the related Todd genus of a complex singular algebraic…

Algebraic Geometry · Mathematics 2013-08-06 Andrzej Weber

It is known that the generalized Nash equilibrium problem can be reformulated as a quasivariational inequality. Our aim in this work is to introduce a variational approach to study the existence of solutions for generalized ordinal Nash…

Optimization and Control · Mathematics 2023-01-31 Orestes Bueno , John Cotrina , Yboon García

This paper formulates the Nash problem for a pair consisting of a toric variety and an invariant ideal and gives an affirmative answer to the problem. We also prove that the minimal log-discrepacy is computed by a divisor corresponding to a…

Algebraic Geometry · Mathematics 2010-07-30 Shihoko Ishii

This work proposes a novel set of techniques for approximating a Nash equilibrium in a finite, normal-form game. It achieves this by constructing a new reformulation as solving a parameterized system of multivariate polynomials with tunable…

Computer Science and Game Theory · Computer Science 2024-11-05 Ian Gemp

A Nash equilibrium has become important solution concept for analyzing the decision making in Game theory. In this paper, we consider the problem of computing Nash equilibria of a subclass of generic finite normal form games. We define…

Computer Science and Game Theory · Computer Science 2015-03-17 Samaresh Chatterji , Ratnik Gandhi

We consider rational varieties with a torus action of complexity one and extend the combinatorial approach via the Cox ring developed for the complete case in earlier work to the non-complete, e.g. affine, case. This includes in particular…

Algebraic Geometry · Mathematics 2025-07-08 Juergen Hausen , Milena Wrobel

In this work we provide effective bounds and classification results for rational $\QQ$-factorial Fano varieties with a complexity-one torus action and Picard number one depending on the invariants dimension and Picard index. This…

Algebraic Geometry · Mathematics 2012-11-26 Elaine Herppich
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