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We will show in this paper that if λ is very close to 1, then can be attained, where M is a compact–manifold with boundary. This result gives a counter–example to the conjecture of de Figueiredo and Ruf in their paper titled "On an inequality by Trudinger and Moser and related elliptic equations" ( Comm. Pure. Appl. Math., 55, 135–152, 2002). [ABSTRACT FROM AUTHOR]

The paper analyzes a Lagrangian system which is controlled by directly assigning some of the coordinates as functions of time, by means of frictionless constraints. In a natural system of coordinates, the equations of motion contain terms which are linear or quadratic with respect to time derivatives of the control functions. After reviewing the basic equations, we explain the significance of the quadratic terms related to geodesics orthogonal to a given foliation. We then study the problem of stabilization of the system to a given point by means of oscillating controls. This problem is first reduced to theweak stability for a related convex-valued differential inclusion, then studied by Lyapunov functions methods. In the last sections, we illustrate the results by means of various mechanical examples. [ABSTRACT FROM AUTHOR]

In this paper, it is proved that with at most $$ O{\left( {N^{{\frac{{65}} {{66}}}} } \right)} $$ exceptions, all even positive integers up to N are expressible in the form $$ p^{2}_{2} + p^{3}_{3} + p^{4}_{4} + p^{5}_{5} $$ . This improves a recent result $$ O{\left( {N^{{\frac{{19193}} {{19200}} + \varepsilon }} } \right)} $$ due to C. Bauer. [ABSTRACT FROM AUTHOR]

In this paper, a class of global optimization problems is considered. Corresponding to each local minimizer obtained, we introduced a new modified function and construct a corresponding optimization subproblem with one constraint. Then, by applying a local search method to the one-constraint optimization subproblem and using the local minimizer as the starting point, we obtain a better local optimal solution. This process is continued iteratively. A termination rule is obtained which can serve as stopping criterion for the iterating process. To demonstrate the efficiency of the proposed approach, numerical examples are solved. [ABSTRACT FROM AUTHOR]

Let u be a solution to a second order elliptic equation with singular potentials belonging to Kato–Fefferman–Phong’s class in Lipschitz domains. An elementary proof of the doubling property for u 2 over balls is presented, if the balls are contained in the domain or centered at some points near an open subset of the boundary on which the solution u vanishes continuously. Moreover, we prove the inner unique continuation theorems and the boundary unique continuation theorems for the elliptic equations, and we derive the ℬ p weight properties for the solution u near the boundary. [ABSTRACT FROM AUTHOR]

The article presents a study on the hyperbolic singular perturbation problems for integrodifferential equations. The authors have obtained new convergence theorems for singular perturbation problems, which generalize some results by H. O. Fattorini and J. Liu before. The idea of hyperbolic singular perturbation problem came from Fattorini's work, wherein the inhomogenous hyperbolic perturbation problem emerge from problems of traffic flow. Some basic assumptions and results of Fattorin's work was used in the study.

A right R–module E over a ring R is said to be maximally injective in case for any maximal right ideal m of R, every R–homomorphism f : m → E can be extended to an R–homomorphism f' : R → E. In this paper, we first construct an example to show that maximal injectivity is a proper generalization of injectivity. Then we prove that any right R–module over a left perfect ring R is maximally injective if and only if it is injective. We also give a partial affirmative answer to Faith's conjecture by further investigating the property of maximally injective rings. Finally, we get an approximation to Faith's conjecture, which asserts that every injective right R–module over any left perfect right self–injective ring R is the injective hull of a projective submodule. [ABSTRACT FROM AUTHOR]

Starting from a second-order Fuchsian differential equation having five regular singular points, an equation obeyed by a function proportional to the first derivative of the solution of the Heun equation, we construct several expansions of the solutions of the general Heun equation in terms of Appell generalized hypergeometric functions of two variables of the first kind. Several cases when the expansions reduce to those written in terms of simpler mathematical functions such as the incomplete Beta function or the Gauss hypergeometric function are identified. The conditions for deriving finite-sum solutions via termination of the series are discussed. In general, the coefficients of the expansions obey four-term recurrence relations; however, there exist certain choices of parameters for which the recurrence relations involve only two terms, though not necessarily successive. For such cases, the coefficients of the expansions are explicitly calculated and the general solution of the Heun equation is constructed in terms of the Gauss hypergeometric functions. [ABSTRACT FROM AUTHOR]

We obtain an asymptotic formula for the mean value of the function τ( n), which is the number of solutions of the equation x ... x = n in natural numbers x, ..., x, in some special sequences of natural numbers. [ABSTRACT FROM AUTHOR]

The article provides information on the applicability of the nonlocal Bitsadze-Samarskii condition equation in solving the linear hyperbolic equations' boundary value problems. It presents the several boundary value problems along with their respective formula as well as the solution. It highlights the theorems of the said equation, depicting the strategies in obtaining solution to the mathematical problem. In addition, it notes the specific functions in computing the mentioned problem. Furthermore, the solvability of the nonlocal Bitsadze-Samarskii condition is also highlighted.

The article provides information on how to determine the eigenvalue problem and solution for Sturm-Liouville mathematical equation. It discusses the procedures in determining the equation's boundary conditions by using the arbitrary complex number and complex-valued function. It presents the equation's fundamental system of solutions, along with initial conditions. It highlights the tips in calculating the equation, where a certain given problem can be reduced into simple mathematical form. Furthermore, the theorems as well as the functions of the equation are also highlighted.

We investigate some properties related to the generalized Newton method for the Fischer-Burmeister (FB) function over second-order cones, which allows us to reformulate the second-order cone complementarity problem (SOCCP) as a semismooth system of equations. Specifically, we characterize the B-subdifferential of the FB function at a general point and study the condition for every element of the B-subdifferential at a solution being nonsingular. In addition, for the induced FB merit function, we establish its coerciveness and provide a weaker condition than Chen and Tseng (Math. Program. 104:293–327, ) for each stationary point to be a solution, under suitable Cartesian P-properties of the involved mapping. By this, a damped Gauss-Newton method is proposed, and the global and superlinear convergence results are obtained. Numerical results are reported for the second-order cone programs from the DIMACS library, which verify the good theoretical properties of the method. [ABSTRACT FROM AUTHOR]

Abstract  We develop a systematic toolbox for analyzing the adaptive dynamics of multidimensional traits in physiologically structured population models with point equilibria (sensu Dieckmann et al. in Theor. Popul. Biol. 63:309–338, 2003). Firstly, we show how the canonical equation of adaptive dynamics (Dieckmann and Law in J. Math. Biol. 34:579–612, 1996), an approximation for the rate of evolutionary change in characters under directional selection, can be extended so as to apply to general physiologically structured population models with multiple birth states. Secondly, we show that the invasion fitness function (up to and including second order terms, in the distances of the trait vectors to the singularity) for a community of N coexisting types near an evolutionarily singular point has a rational form, which is model-independent in the following sense: the form depends on the strategies of the residents and the invader, and on the second order partial derivatives of the one-resident fitness function at the singular point. This normal form holds for Lotka–Volterra models as well as for physiologically structured population models with multiple birth states, in discrete as well as continuous time and can thus be considered universal for the evolutionary dynamics in the neighbourhood of singular points. Only in the case of one-dimensional trait spaces or when N  =  1 can the normal form be reduced to a Taylor polynomial. Lastly we show, in the form of a stylized recipe, how these results can be combined into a systematic approach for the analysis of the (large) class of evolutionary models that satisfy the above restrictions. [ABSTRACT FROM AUTHOR]

The article examines the existence of solutions for weighted p(x)-Laplacian ordinary boundary value problem. The method used in this study is based on Leray-Schauder degree. As an application, the existence of weak solutions for p(x)-Laplacian partial differential equations is given. On the p(x)-Laplacian problems, there is a possibility that it does not have the first eigenvalue and the first eigenfunction. Several sub-super-solution theorems for the existence of solutions for weighted p(x)-Laplacian equation with Dirichlet, Robin, and Periodic boundary value conditions are established.

The article analyzes the boundary asymptotic behavior of solutions for weighted p(x)-Laplacian equations that take infinite value on a bounded domain. It was found that the boundary asymptotic of solutions of the Laplacian function is continuous and positive. The p(x)-Laplacian possesses more complicated inhomogeneous nonlinearities, thus, some special techniques are needed. Its main difficulty arises from the lack of compactness. The uniqueness and asymptotic behavior of solutions for problem is a nonnegative function which is allowed to vanish on the boundary.

Based on the Orlov and Shulman’s M operator, the additional symmetries and the string equation of the CKP hierarchy are established, and then the higher order constraints on L l are obtained. In addition, the generating function and some properties are also given. In particular, the additional symmetry flows form a new infinite dimensional algebra $$W^C_{1+\infty}$$ , which is a subalgebra of W 1+∞. [ABSTRACT FROM AUTHOR]

Let R be an exchange ring with primitive factors artinian. We prove that there exists a u∈ U( R) such that 1 R ± u ∈ U( R), if and only if for any a∈ R, there exists a u ∈ U( R) such that a ± u ∈ U( R). Furthermore, we prove that, for any A ∈ M n ( R)( n ≥ 2), there exists a U ∈ GL n ( R) such that A ± U ∈ GL n ( R). [ABSTRACT FROM AUTHOR]

The article presents a study on the mathematical equation of two-dimensional linear differential systems with deviating arguments using Kneser type solutions. It presents an equation with positive coefficient and two linearly independent solutions. The article also evaluates the existence and uniqueness of these types of solutions. It proves that Kneser type solution is equivalent to nonvanishing of the Wronskian fundamental system and positivity of Green's function of the problem.

The article presents a research on the discontinuous quasilinear elliptic variational-hemivariational inequalities which involves the ρ-Laplacian. It also notes on the extension of the theory for discontinuous problems with the use of the method of sub- and supersolutions and compared on the results of S. Carl. It also aims to prove the existence of extremal solutions within a given order interval of sub- and supersolutions. It also gives example of the construction of sub- and supersolutions.

The article presents a research on the iterative methods for generalized von Foerster equations with functional dependence. It examines the meeting of a natural iterative method to the exact solution of a differential-functional von Foerster-type equation that notes a single population depending on its total size, past time and states densities. It also assumes either Perron comparison conditions and some monotonicity. It also investigates on the natural conditions which ensures convergence of iterative methods.

The equations under consideration have the following structure: where 0 < x n < ∞, ( x 1, ..., x n−1) ∈ Ω, Ω is a bounded Lipschitz domain, $$f(0,x_n ) \equiv 0,\tfrac{{\partial f}}{{\partial u}}(0,x_n ) \equiv 0$$ is a function that is continuous and monotonic with respect to u, and all coefficients are bounded measurable functions. Asymptotic formulas are established for solutions of such equations as x n → + ∞; the solutions are assumed to satisfy zero Dirichlet or Neumann boundary conditions on ∂Ω. Previously, such formulas were obtained in the case of a ij, ai depending only on ( x 1, ..., x n−1). [ABSTRACT FROM AUTHOR]

The classical proofs of the De Giorgi–Nash–Moser Theorem are based on the iteration of some inequality through countably many concentric balls. In this note, we present a new approach to the Hölder continuity of solutions to elliptic equations in divergence form, which avoids any form of discrete iteration. In particular, we prove that a suitable energy function satisfies a differential inequality, whose integration yields a new proof of the crucial step in the regularity result. [ABSTRACT FROM AUTHOR]

Based on a continuation theorem of Mawhin, the existence of a positive periodic solution for a nonlinear difference system is studied. [ABSTRACT FROM AUTHOR]

Focuses on multivalued feedback with semicontinuity property. Unknown disturbance in equations; Mathematical models of controlled objects; Mutivalued initial conditions and multivalued boundary conditions; Differential games with functionals.

An extensible beam equation with a stochastic force of a white noise type is studied, Lyapunov functions techniques being used to prove existence of global mild solutions and asymptotic stability of the zero solution. [ABSTRACT FROM AUTHOR]

Analyzes the existence of solitary waves in the case of a preliminary deformation. Assessment of the complete nonlinear system of equations of running waves; Consideration of plane wave motions in an inhomogeneous nonlinear elastic medium which is in a predeformed state; Expansion of the unknown vector function.

The article analyzes enough conditions on the lower order coefficients of the parabolic equations in the second-order. It discusses the solution of the Cauchy problem in classes of rising initial functions stables x-uniformly to zero on each compact set K ∈ RN. It presents the reality of coefficients αik = αki (i, k = 1, 2, ..., N) and the satisfaction of the uniform parabolicity conditions; Ǝ there exist constants ɻ0 0 and ɻ1.