Monomial conditions on rings

Drazin introduced the notion ofpivotal monomial, a condition on the evaluations of monomials in a ring, and characterized simple artinian rings as those primitive rings which have pivotal monomials. In this paper we consider monomial conditions related to pivotal monomials. The two major results are a characterization of prime Goldie rings in terms of pivotal monomials, and a characterization of the socle of a primitive ring in terms of generalized pivotal monomials.     

Time series model based on global structure of complete genome

A time series model based on the global structure of the complete genome is proposed. Three kinds of length sequences of the complete genome are considered. The correlation dimensions and Hurst exponents of the length sequences are calculated. Using these two exponents, some interesting results related to the problem of classification and evolution relationship of bacteria are obtained.     

Relation between two measures of the computation complexity for systems of monomials

For a class of matrices defining exponents of variables in a system of monomials, a nontrivial lower bound of complexity is found (where the complexity is defined as the minimum number of multiplications required to compute the system starting from variables). An example of a sequence of matrices (systems of monomials, respectively) is also given so that the usage of inverse values of variables (in addition to the variables themselves) makes the complexity asymptotically two times less.     

对称本原有向图广义重上指数的极图刻划

一个有向图Ｄ称为本原有向图,若存在某自然数ｋ,使Ｄ中任一点ｕ到任 一点ｖ都有长为ｋ之途径．若Ｄ是一个对称有向图,则Ｄ是本原的当且仅当Ｄ对 应的无向图连通且至少包含一个奇圈。文［２］给出了具有最小奇圈长ｒ的ｎ阶对称本 原有向图广义ｋ重上指数的最大数．本文将在此基础上,给出其极图的完全刻划．     

On fully indecomposable exponent for primitive boolean matrices with symmetric ones

If A is a primitive matrix, then there is a smallest power of A (its fully indecomposable exponent) which is fully indecomposable, and a smallest power of A (its strict fully indecomposable exponent) starting from which all powers are fully indecomposable. We obtain bounds on these two exponents for primitive Boolean matrices with symmetric one's.     

The particular solutions for thin plates resting on Pasternak foundations under arbitrary loadings

Analytical particular solutions of splines and monomials are obtained for problems of thin plate resting on Pasternak foundation under arbitrary loadings, which are governed by a fourth‐order partial differential equation (PDEs). These analytical particular solutions are valuable when the arbitrary loadings are approximated by augmented polyharmonic splines (APS) constructed by splines and monomials. In our derivations, the real coefficient operator in the governing equation is decomposed into two complex coefficient operators whose particular solutions are known in literature. Then, we use the difference trick to recover the analytical particular solutions of the original operator. In addition, we show that the derived particular solution of spline with its first few directional derivatives are bounded as r → 0. This solution procedure may have the potential in obtaining analytical particular solutions of higher order PDEs constructed by products of Helmholtz‐type operators. Furthermore, we demonstrate the usages of these analytical particular solutions by few numerical cases in which the homogeneous solutions are complementarily solved by the method of fundamental solutions (MFS). © 2009 Wiley Periodicals, Inc. Numer Methods Partial Differential Eq, 2010     

Multiplicities of Pfaffian intersections,and the Łojasiewicz inequality

An effective estimate for the local multiplicity of a complete intersection of complex algebraic and Pfaffian varieties is given, based on a local complex analog of the Rolle-Khovanskii theorem. The estimate is valid also for the properly defined multiplicity of a non-isolated intersection. It implies, in particular, effective estimates for the exponents of the polar curves, and the exponents in the ojasiewicz inequalities for Pfaffian functions. For the intersections defined by sparse polynomials, the multiplicities outside the coordinate hyperplanes can be estimated in terms of the number of non-zero monomials, independent of degrees of the monomials.     

Gcd of multivariate polynomials via Newton polytopes

We study geometric criteria to determine coprimality between multivariate polynomials. Our main contribution is the development of a polynomial-time algorithm (on the number of monomials) that detects coprimality of multivariate polynomials using Newton polytopes. We also show how to construct the gcd of two bivariate polynomials using their Newton polygons.     

On fully indecomposable exponent for primitive boolean matrices with symmetric ones

If A is a primitive matrix, then there is a smallest power of A (its fully indecomposable exponent) which is fully indecomposable, and a smallest power of A (its strict fully indecomposable exponent) starting from which all powers are fully indecomposable. We obtain bounds on these two exponents for primitive Boolean matrices with symmetric one's.     

On the perron sign change effect for Lyapunov characteristic exponents of solutions of differential systems

The Perron effect is the effect in which the characteristic Lyapunov exponents of solutions of a differential system change sign from negative to positive when passing to a perturbed system. We show that this effect is realized on all nontrivial solutions of two two-dimensional systems: an original linear system with negative characteristic exponents and a perturbed system with small perturbations of arbitrary order m > 1 in a neighborhood of the origin, all of whose nontrivial solutions have positive characteristic exponents. We compute the exact positive value of the characteristic exponents of solutions of the two-dimensional nonlinear Perron system with small second-order perturbations, which realizes only a partial Perron effect.     

On graphs having domination number half their order

In this paper we present a characterization of connected graphs of order 2n with domination numbern. Using this class of graphs, we determine an infinite class of graphs with the property that the domination number of the product of any two is precisely the product of the domination numbers.     

Codiameters of 3‐connected 3‐domination critical graphs

A graph G is 3‐domination critical if its domination number γ is 3 and the addition of any edge decreases γ by 1. Let G be a 3‐connected 3‐domination critical graph of order n. In this paper, we show that there is a path of length at least n?2 between any two distinct vertices in G and the lower bound is sharp. © 2002 John Wiley & Sons, Inc. J Graph Theory 39: 76–85, 2002     

Exact integration formulas for the finite volume element method on simplicial meshes

This article considers the technological aspects of the finite volume element method for the numerical solution of partial differential equations on simplicial grids in two and three dimensions. We derive new classes of integration formulas for the exact integration of generic monomials of barycentric coordinates over different types of fundamental shapes corresponding to a barycentric dual mesh. These integration formulas constitute an essential component for the development of high‐order accurate finite volume element schemes. Numerical examples are presented that illustrate the validity of the technology. © 2007 Wiley Periodicals, Inc. Numer Methods Partial Differential Eq, 2007     

Large Critical Exponents for Some Second Order Uniformly Elliptic Operators

In this paper we investigate the critical exponents of two families of Pucci's extremal operators. The notion of critical exponent that we have chosen for these fully nonlinear operators which are not variational is that of threshold between existence and nonexistence of the solutions for semilinear equations with pure power nonlinearities. Interesting new exponents appear in this context.     

The Mann–Whitney <Emphasis Type="Italic">U</Emphasis>-statistic for α-dependent sequences

We give the asymptotic behavior of the Mann–Whitney U-statistic for two independent stationary sequences. The result applies to a large class of short-range dependent sequences, including many nonmixing processes in the sense of Rosenblatt [17]. We also give some partial results in the long-range dependent case, and we investigate other related questions. Based on the theoretical results, we propose some simple corrections of the usual tests for stochastic domination; next we simulate different (nonmixing) stationary processes to see that the corrected tests perform well.     

Formal power series with cyclically ordered exponents

We define and study a notion of ring of formal power series with exponents in a cyclically ordered group. Such a ring is a quotient of various subrings of classical formal power series rings. It carries a two variable valuation function. In the particular case where the cyclically ordered group is actually totally ordered, our notion of formal power series is equivalent to the classical one in a language enriched with a predicate interpreted by the set of all monomials.Received: 24 February 2003     

On graphs for which the connected domination number is at most the total domination number

In this note, we give a finite forbidden subgraph characterization of the connected graphs for which any non-trivial connected induced subgraph has the property that the connected domination number is at most the total domination number. This question is motivated by the fact that any connected dominating set of size at least 2 is in particular a total dominating set. It turns out that in this characterization, the total domination number can equivalently be substituted by the upper total domination number, the paired-domination number and the upper paired-domination number, respectively. Another equivalent condition is given in terms of structural domination.     

Characteristic sequences of non-associative algebras

Abstract

In this paper, we provide the complete characterization of integer sequences that are characteristic sequences for general non-associative algebras, i.e., we determine the set of combinatorial properties which hold for all characteristic sequences and construct corresponding algebras for integer sequences satisfying them. The obtained information on characteristic sequences is then applied to investigate the realizability problem for the length function. In particular, we determine certain segment of values which are not realizable as values of the length function.     

Average distance and domination number revisited

We give a short proof for Dankelmann’s characterization of connected graphs of given order and domination number that maximize the average distance [P. Dankelmann, Average distance and the domination number, Discrete Appl. Math. 80 (1997) 21-35].