Generic lattice ideals

A concept of genericity is introduced for lattice ideals (and hence for ideals defining toric varieties) which ensures nicely structured homological behavior. For a generic lattice ideal we construct its minimal free resolution and we show that it is induced from the Scarf resolution of any reverse lexicographic initial ideal.

     

Wedge Operations and Doubling Operations of Real Toric Manifolds

This paper deals with two things.First,the cohomology of canonical extensions of real topological toric manifolds is computed when coefficient ring G is a commutative ring in which 2 is unit in G.Second,the author focuses on a specific canonical extensions called doublings and presents their various properties.They include existence of infinitely many real topological toric manifolds admitting complex structures,and a way to construct infinitely many real toric manifolds which have an odd torsion in their cohomology groups.Moreover,some questions about real topological toric manifolds related to Halperin's toral rank conjecture are presented.     

一类非凸区域的拟法锥构造方法及其在非凸规划求解中的应用

本文给出基于球形的一类满足拟法锥条件区域的拟法锥构造方法,基于该可行域的拟法锥,建立求解在该类非凸区域上的规划问题的K-K-T点的部分凝聚同伦组合方程,并证明了该同伦内点法的整体收敛性,给出实现同伦内点法的具体数值跟踪算法步骤,并通过数值例子证明算法是可行的和有效的．     

Jet schemes and minimal toric embedded resolutions of rational double point singularities

Using the structure of the jet schemes of rational double point singularities, we construct “minimal embedded toric resolutions” of these singularities. We also establish, for these singularities, a correspondence between a natural class of irreducible components of the jet schemes centered at the singular locus and the set of divisors which appear on every “minimal embedded toric resolution”. We prove that this correspondence is bijective except for the E₈ singulartiy. This can be thought as an embedded Nash correspondence for rational double point singularities.     

Deformations of Codimension 2 Toric Varieties

We prove Sturmfels' conjecture that toric varieties of codimension two have no other flat deformations than those obtained by Gröbner basis theory.     

同伦方法求解非凸区域Brouwer不动点问题

本文构造了一个新的求解非凸区域上不动点问题的内点同伦算法,并在弱法锥(见定义2．1(2))和适当的条件下,证明了算法的全局收敛性．本文所给的条件比外法锥条件更加一般．     

An LMI description for the cone of Lorentz-positive maps II

Let L _n be the n-dimensional second-order cone. A linear map from ? ^m to ? ⁿ is called positive if the image of L _m under this map is contained in L _n . For any pair (n,?m) of dimensions, the set of positive maps forms a convex cone. We construct a linear matrix inequality of size (n???1)(m???1) that describes this cone.     

Local Equations for the Toric Hilbert Scheme

We obtain local equations for the toric Hilbert scheme, which parametrizes all ideals with the same multigraded Hilbert function as a given toric ideal. We also prove a conjecture of Sturmfels' providing a criterion for an ideal to have such a Hilbert function.     

On a Family of Gradient-Type Projection Methods for Nonlinear Ill-Posed Problems

Abstract

We propose and analyze a family of successive projection methods whose step direction is the same as the Landweber method for solving nonlinear ill-posed problems that satisfy the Tangential Cone Condition (TCC). This family encompasses the Landweber method, the minimal error method, and the steepest descent method; thus, providing an unified framework for the analysis of these methods. Moreover, we define new methods in this family, which are convergent for the constant of the TCC in a range twice as large as the one required for the Landweber and other gradient type methods. The TCC is widely used in the analysis of iterative methods for solving nonlinear ill-posed problems. The key idea in this work is to use the TCC in order to construct special convex sets possessing a separation property, and to successively project onto these sets. Numerical experiments are presented for a nonlinear two-dimensional elliptic parameter identification problem, validating the efficiency of our method.     

An Improvement of Existence Theorems of Additive Selection Maps for Sub-additive Set-valued Maps

In this paper, we will construct a new class of subadditive set-valued maps and use Cantor theorem to prove that the set-valued map has an unique additive selection map when the set-valued map satisfies some certain conditions, and then compare the obtained result with the well-known results.     

A proximal augmented Lagrangian method for equilibrium problems

Considering a recently proposed proximal point method for equilibrium problems, we construct an augmented Lagrangian method for solving the same problem in reflexive Banach spaces with cone constraints generating a strongly convergent sequence to a certain solution of the problem. This is an inexact hybrid method meaning that at a certain iterate, a solution of an unconstrained equilibrium problem is found, allowing a proper error bound, followed by a Bregman projection of the initial iterate onto the intersection of two appropriate halfspaces. Assuming a set of reasonable hypotheses, we provide a full convergence analysis.     

用Hadamard方法构造惯性流形

本文用Ｈａｄａｍａｒｄ方法为一类带有非线性项Ｒ：Ｄ（Ａ）→Ｈ的无限维耗散动力系统建立惯性流形．在建立惯性流形的过程中，系统的一种“不变锥性质”被充分利用着．这里，对惯性流形存在性至关紧要的谱间隙条件是．     

Viro Method for the Construction of Real Complete Intersections

The Viro method is a powerful construction method of real nonsingular algebraic hypersurfaces with prescribed topology. It is based on polyhedral subdivisions of Newton polytopes. A combinatorial version of the Viro method is called combinatorial patchworking and arises when the considered subdivisions are triangulations. B. Sturmfels has generalized the combinatorial patchworking to the case of real complete intersections. We extend his result by generalizing the Viro method to the case of real complete intersections.     

The set of toric minimal log discrepancies

We describe the set of minimal log discrepancies of toric log varieties, and study its accumulation points. This work is supported by a 21st Century COE Kyoto Mathematics Fellowship, and a JSPS Grant-in-Aid No 17740011.     

Isotone tangent cones and nonsmooth optimization

A simple but quite general method of formulating necessary optimality conditions for an abstract mathematical program is presented. This method centers around tangent cones which are isotone with respect to inclusion. The optimality conditions derived by this method generalize standard necessary conditions of differentiate, convex, and nonsmooth mathematical programming.     

A note on finite abelian gerbes over toric Deligne-Mumford stacks

Any toric Deligne-Mumford stack is a -gerbe over the underlying toric orbifold for a finite abelian group . In this paper we give a sufficient condition so that certain kinds of gerbes over a toric Deligne-Mumford stack are again toric Deligne-Mumford stacks.

     

Extension of Transient Resolvents

For a submarkovian resolvent U=(U )_>0 with bounded initial kernel U ₀ on a Radon space X, we construct a minstable cone of potentials C on a compact metrizable space YX such that U extends to a subordonated (to C) resolvent on Y.     

Toric Initial Ideals of Δ-Normal Configurations: Cohen-Macaulayness and Degree Bounds

A normal (respectively, graded normal) vector configuration\({\cal A}\) defines the toric ideal \({I}_{\cal A}\) of a normal (respectively, projectively normal) toric variety. These ideals are Cohen-Macaulay, and when \({\cal A}\) is normal and graded, \({I}_{\cal A}\) is generated in degree at most the dimension of \({I}_{\cal A}\). Based on this, Sturmfels asked if these properties extend to initial ideals—when \({\cal A}\) is normal, is there an initial ideal of \({I}_{\cal A}\) that is Cohen-Macaulay, and when \({\cal A}\) is normal and graded, does \({I}_{\cal A}\) have a Gröbner basis generated in degree at most dim(\({I}_{\cal A}\)) ? In this paper, we answer both questions positively for Δ-normal configurations. These are normal configurations that admit a regular triangulation Δ with the property that the subconfiguration in each cell of the triangulation is again normal. Such configurations properly contain among them all vector configurations that admit a regular unimodular triangulation. We construct non-trivial families of both Δ-normal and non-Δ-normal configurations.     

BOUNDING PYRAMIDS AND BOUNDING CONES FOR TRIANGULAR BEZIER SURFACES

1. IntroductionA 6ounding pyramid/cone of a rational B6zier surface patch is a pyramid/cone whichhas the property that if its vertex is translated to any point on the B6zier patch, thepatch will lie completely outside the pyramid/cone. These kinds of pyramids/conesare useful tools in detecting closed loops in surface/surface intersections[2, 3] and determining directions for which a surface is single valued[5]. While methods of finding bounding pyramids and bounding cones for rectangular B6zi…     

随机二阶锥二次规划逆问题的SAA方法

本文讨论一类随机的二阶锥二次规划逆问题, 该模型是一个含有二阶锥互补约束的随机二次规划模型, 对解释部分实际问题有着一定的优势。为了求解该模型, 本文引入了随机抽样技术和互补约束光滑化近似技术, 得到问题的近似子问题。本文证明, 只要子问题的解是存在且收敛的, 则该极限以概率一是原问题的C-稳定点; 若严格互补条件和二阶必要性条件成立, 则该极限以概率1是原问题的M-稳定点。一个简单的数值实验验证了该算法具有一定的可行性。