Parametrizing Over ℤ Integral Values of Polynomials Over ℚ

Given a polynomial f ∈ ?[X] such that f(?) ? ?, we investigate whether the set f(?) can be parametrized by a multivariate polynomial with integer coefficients, that is, the existence of g ∈ ?[X ₁,…, X _m ] such that f(?) = g(? ^m ). We offer a necessary and sufficient condition on f for this to be possible. In particular, it turns out that some power of 2 is a common denominator of the coefficients of f, and there exists a rational β with odd numerator and odd prime-power denominator such that f(X) = f(β ?X). Moreover, if f(?) is likewise parametrizable, then this can be done by a polynomial in one or two variables.     

ON POLYNOMIAL AUTOMORPHISM IDENTITY SETS AND IDENTITY POLYNOMIALS

In this paper, we propose a new condition for hypersurfaces to be polynomial automorphism identity sets. This new condition can be used to give a new proof of Mckay-Wang's problem. Moreover, we also study the concepts of identity polynomials, and give a criterion for a polynomial to be identity polynomial.     

关于多项式映射自同构恒等集的一个注记

本文给出了判定一个仿射代数集是否是一个自同构恒等集的充分条件.作为一个推论,我们给出了Mckay-Wang的一个问题的一个新证明.我们也给出了一些具体的例子来说明主要的定理.     

On four-sheeted polynomial mappings of ℂ2. I. The case of an irreducible ramification curve

The paper is devoted to the Jacobian Conjecture: a polynomial mappingf²² with a constant nonzero Jacobian is polynomially invertible. The main result of the paper is as follows. There is no four-sheeted polynomial mapping whose Jacobian is a nonzero constant such that after the resolution of the indeterminacy points at infinity there is only one added curve whose image is not a point and does not belong to infinity.Translated fromMatematicheskie Zametki, Vol. 64, No. 6, pp. 847–862, December, 1998.The authors are grateful to A. G. Vitushkin and P. Cassou-Nogues for useful discussions.This research was supported by the Russian Foundation for Basic Research under grant No. 96-01-01218. The work of the second author was done under the financial support of DGICYT (Spain), grant No. SAB95-0502.     

Sur les feuilletages algébriques de Rolle

L'objet de ce travail est l'étude des feuilletages algébriques de Rolle dans . On montre que leur restriction au complémentaire d'un nombre fini de feuilles possède une structure de produit. On précise aussi la topologie de certaines de leurs feuilles. Received: June 22, 1996     

On a certain geometric mean of the values of a polynomial

The maximum of the geometric mean of the values of a polynomial in the vertices of a regularkgon inscribed into the unit circle is greater than or equal to its Mahler measure. It also tends to the Mahler measure ask tends to infinity. We give quantitative versions of this statement: the upper bounds for the ratio of these two quantities. Partially supported by the Lithuanian State Science and Studies Foundation. Published in Lietuvos Matematikos Rinkinys, Vol. 40, No. 1, pp. 17–27, January–March, 2000.     

Sur la séparation des racines des polynômes et une question de Sprindžuk

Résumé Nous établissons une nouvelle minoration de la distance entre deux racines d’un polynôme à coefficients entiers, que nous appliquons à une question de théorie métrique des nombres posée par Sprindžuk.We establish a new lower bound for the distance between two roots of an integer polynomial. We apply it to a question in metric number theory posed by Sprindžuk.2000 Mathematics Subject Classification: Primary—11C08     

关于单形中面的不等式

关于Eⁿ中的k维单形Ω_k(2≤k≤n),介绍了Ω_k的k-1维中面的概念.由En中的k维单形Ω_k(2≤k≤n),介绍了Ω_k的k-1维中面的概念.由Eⁿ中的有限点集可产生不同维数的单形,建立了这些单形中面面积的几何不等式.     

Unimodal mappings and Li-Yorke chaos

Conditions for unimodal mappings to have domains with a Li-Yorke chaotic behavior of trajectories are found. Translated fromMatematicheskie Zametki, Vol. 63, No. 5, pp. 679–689, May, 1998.     

How to solve the polynomial ordinary differential equations

This paper discussed how to solve the polynomial ordinary differential equations. At first, we construct the theory of the linear equations about the unknown one variable functions with constant coefficients. Secondly, we use this theory to convert the polynomial ordinary differential equations into the simultaneous first order linear ordinary differential equations with constant coefficients and quadratic equations. Thirdly, we work out the general solution of the polynomial ordinary differential equations which is no longer concerned with the differential. Finally, we discuss the necessary and sufficient condition of the existence of the solution.     

Integrally Closed Domains,Minimal Polynomials,and Null Ideals of Matrices

Abstract

We show that every element of the integral closure D′ of a domain D occurs as a coefficient of the minimal polynomial of a matrix with entries in D. This answers affirmatively a question of Brewer and Richman, namely, if integrally closed domains are characterized by the property that the minimal polynomial of every square matrix with entries in D is in D[x]. It follows that a domain D is integrally closed if and only if for every matrix A with entries in D the null ideal of A, N _D (A)?=?{f?∈?D[x]?∣?f(A)?=?0} is a principal ideal of D[x].     

近似凸集的某些性质

主要研究了两类近似凸集的关系和性质.首先,举例说明两类近似凸集没有相互包含关系.其次,在近似凸集(nearly convex)条件下,证明了在一定条件下函数上图是近似凸集与凸集的等价关系.同时,考虑了近似凸函数与函数上图是近似凸集的等价刻画、近似凸函数与函数水平集是近似凸集的必要性,并用例子说明近似凸函数与函数水平集是...