Inverse functions of polynomials and orthogonal polynomials as operator monotone functions

We study the operator monotonicity of the inverse of every polynomial with a positive leading coefficient. Let be a sequence of orthonormal polynomials and the restriction of to , where is the maximum zero of . Then and the composite are operator monotone on . Furthermore, for every polynomial with a positive leading coefficient there is a real number so that the inverse function of defined on is semi-operator monotone, that is, for matrices , implies

     

Numerical computation of characteristic polynomials of Boolean functions and its applications

We study the problem of evaluation of characteristic polynomials of Boolean functions with applications to combinational circuit verification. Two Boolean functions are equivalent if and only if their corresponding characteristic polynomials are identical. However, to verify the equivalence of two Boolean functions it is often impractical to construct the corresponding characteristic polynomials due to a possible exponential blow-up of the terms of the polynomials. Instead, we compare their values at a sample point without explicitly constructing the characteristic polynomials. Specifically, we sample uniformly at random in a unit cube and determine whether two characteristic polynomials are identical by their evaluations at the sample point; the error probability is zero when there are no round-off errors. In the presence of round-off errors, we sample on regular grids and analyze the error probability. We discuss in detail the Shannon expansion for characteristic polynomial evaluation. This revised version was published online in June 2006 with corrections to the Cover Date.     

On the controllability of nonlinear systems with applications to polynomial systems

The purpose of this paper is to examine the controllability for a class of nonlinear control systems of the form $$\frac{{d\phi t}}{{dt}} = X_0 (\phi t) + \sum\limits_{j = 1}^r {u_j (t)X_j } (\phi _t )$$ Our general theorem is stated in terms of differential geometry, but it will be applied to concrete systems such that coefficientsX ₀,..,X _r are polynomials.     

Finding all solutions to polynomial systems and other systems of equations

In a previous paper, the authors suggested a procedure for obtaining all solutions to certain systems ofn equations inn complex variables. The idea was to start with a trivial system of equations to which all solutions were easily known. The trivial system was then perturbed into the given system. During the perturbation process, one followed the solution paths from each of the trivial solutions into the solutions of the given system. All solutions to the given system were thereby obtained.This paper utilizes a different approach that eliminates the requirement of the previous paper for a leading dominating term in each equation. We add a dominating term artificially and then fade it. Also we rely on mathematically more fundamental concepts from differential topology. These advancements permit the calculation of all solutions to arbitrary polynomials and to various other systems ofn equations inn complex variables. In addition, information on the number of solutions can be obtained without calculation.Work supported in part by NSF Grant No. MCS77-15509 and ARO Grant No. DAAG-29-78-G-0160.Work supported in part by ARO Grant No. DAAG-29-78-G-0160     

On the solutions to polynomial systems obtained by homotopy methods

Summary A natural class of homotopy methods for solving polynomial systems is considered. It is shown that at least one solution from each connected component of the solution set is obtained. This generalizes the results of previous papers which concentrated on isolated solutions, i.e. connected components with one single point. The number of solution paths ending in a connected component is independent of the particular homotopy in use and defines in a natural way the multiplicity of the connected component. A few numerical experiments illustrate the obtained results.     

Faber polynomials with applications to univalent functions with quasiconformal extensions

We obtain some convergence properties concerning Faber polynomials and apply them to studying univalent functions with quasiconformal extensions. In particular, by introducing an operator on the usual l ² space, we obtain some new characterizations of quasiconformal extendablity and asymptotic conformality for univalent functions.     

Lower bounds for real solutions to sparse polynomial systems

We show how to construct sparse polynomial systems that have non-trivial lower bounds on their numbers of real solutions. These are unmixed systems associated to certain polytopes. For the order polytope of a poset P this lower bound is the sign-imbalance of P and it holds if all maximal chains of P have length of the same parity. This theory also gives lower bounds in the real Schubert calculus through the sagbi degeneration of the Grassmannian to a toric variety, and thus recovers a result of Eremenko and Gabrielov.     

Theory of functional solutions to quasilinear systems of conservation laws and its applications

The paper deals with the justification of correctness of problems for nonlinear equations that have applications in mathematical physics. Basic mathematical structures connected with problems of convergence of approximate methods are pointed out and investigated, and theorems on global solvability of the Cauchy problem for quasilinear and semilinear equations, including the Boltzmann and Smoluchowski equations for space-inhomogeneous media, are proved. Bibliography: 30 titles. Translated from Trudy Seminara imeni I. G. Petrovskogo, No. 20, pp. 81–120, 1997.     

Finding multiple solutions to elliptic systems with polynomial nonlinearity

Elliptic systems with polynomial nonlinearity usually possess multiple solutions. In order to find multiple solutions, such elliptic systems are discretized by eigenfunction expansion method (EEM). Error analysis of the discretization is presented, which is different from the error analysis of EEM for scalar elliptic equations in three aspects: first, the choice of framework for the nonlinear operator and the corresponding isomorphism of the linearized operator; second, the definition of an auxiliary problem in deriving the relation between the L² norm and H¹ norm of the Ritz projection error; third, the bilinearity/nonbilinearity of the linearized variational forms. The symmetric homotopy for the discretized equations preserves not only D₄ symmetry, but also structural symmetry. With the symmetric homotopy, a filter strategy and a finite element Newton refinement, multiple solutions to a system of semilinear elliptic equations arising from Bose–Einstein condensate are found.     

Computing all solutions to polynomial systems using homotopy continuation

In a previous paper we described a new method for defining homotopies for finding all solutions to polynomial systems. A major feature of this new approach is that the start system for the homotopy need not be a “random” or “generic” system. Also, homotopy paths are strictly increasing in the homotopy parameter. In this paper we establish some principles of implementation and report on the performance of programs that use the new homotopies. A feature of our implementation is that we eliminate divergent paths entirely. We include performance statistics for homotopies derived from more traditional approaches for comparison. Generally, the new approach is faster and more reliable.     

Bivariate delta-evolution equations and convolution polynomials: Computing polynomial expansions of solutions

This paper describes an application of Rota and collaborator’s ideas, about the foundation on combinatorial theory, to the computing of solutions of some linear functional partial differential equations. We give a dynamical interpretation of the convolution families of polynomials. Concretely, we interpret them as entries in the matrix representation of the exponentials of certain contractive linear operators in the ring of formal power series. This is the starting point to get symbolic solutions for some functional-partial differential equations. We introduce the bivariate convolution product of convolution families to obtain symbolic solutions for natural extensions of functional-evolution equations related to delta-operators. We put some examples to show how these symbolic methods allow us to get closed formulas for solutions of genuine partial differential equations. We create an adequate framework to base theoretically some of the performed constructions and to get some existence and uniqueness results.     

On blow-up solutions of polynomial Kolmogorov systems

We investigate the existence problem for blow-up solutions of the polynomial Kolmogorov systems. We find sets of initial values of the blow-up solutions. We also consider a method of finding upper bounds for the blow-up time of these solutions.     

A transformation to avoid solutions at infinity for polynomial systems

In finding all solutions to polynomial systems, the existence of solutions at infinity makes the problem more difficult, particularly when a continuation method is being used as the solution technique. Systems with solutions at infinity do arise in applications; for example, in computer graphics and geometric modeling. In this paper, a simple transformation of the system is given which eliminates solutions at infinity.     

Results on uniqueness of entire functions whose difference polynomials share a polynomial

In this paper, we use the concept of weighted sharing of values to investigate the uniqueness results when two difference polynomials of entire functions share a nonzero polynomial or a small function with a finite weight.We also investigate the situation when the original functions share 0 CM. The obtained results improve some recent related results of X. Li et al. [Ann. Polon. Math, 102 (2011), 111-127] and that of W. Li et al. [Bull. Malay. Math. Sci. Soc., 39 (2016), 499-515].     

Jackson theorems for generalized polynomials with special applications to trigonometric and hyperbolic functions

Jackson theorems for polynomials are transformed into Jackson theorems for more general function classes by way of special operators. In particular, Jackson-Timan and inverse theorems are shown for classes of trigonometric and hyperbolic functions.     

Optical soliton and elliptic functions solutions of Sasa-satsuma dynamical equation and its applications

The Sasa-satsuma(SS) dynamical equation interpret propagation of ultra-short and femto-second pulses in optical fibers. This dynamical model has important physical significance.In this article, two mathematical techniques namely, improved F-expansion and improved auxiliary methods are utilized to construct the several types of solitons such as dark soliton, bright soliton, periodic soliton, Elliptic function and solitary waves solutions of Sasa-satsuma dynamical equation. These results have imperative applications in sciences and other fields, and constructive to recognize the physical structure of this complex dynamical model. The computing work and obtained results show the influence and effectiveness of current methods.     

A system of biorthogonal polynomials and its applications

Translated from Ukrainskii Matematicheskii Zhurnal, Vol. 41, No. 7, pp. 961–965, July, 1989.