Analyticity of the semigroup associated with the fluid-rigid body problem and local existence of strong solutions

In this paper, we study the linear operator associated with the fluid-rigid body problem. The operator was first introduced by T. Takahashi and M. Tucsnak (2004) [22]. For the general three-dimensional case, we prove that the corresponding semigroup is analytic on (p?2). In particular, when the solid is a ball in R³, the corresponding semigroup is analytic on L²(R³)∩Lp(R³)(p?6). And for this case, a unique local strong solution to the fluid-rigid body problem is derived.     

Existence of self-dual non-topological solutions in the Chern–Simons Higgs model

In this paper we investigate the existence of non-topological solutions of the Chern–Simons Higgs model in R². A long standing problem for this equation is: Given N vortex points and β>8π(N+1), does there exist a non-topological solution in R² such that the total magnetic flux is equal to β/2? In this paper, we prove the existence of such a solution if . We apply the bubbling analysis and the Leray–Schauder degree theory to solve this problem.     

Multiple non semi‐trivial solutions of systems of Kirchhoff‐type equations with discontinuous nonlinearities in RN

In the present paper, we study the problem of multiple non semi‐trivial solutions for the following systems of Kirchhoff‐type equations with discontinuous nonlinearities (1.1) where F∈C¹(R^N×R⁺×R⁺,R),V∈C(R^N,R), and By establishing a new index theory, we obtain some multiple critical point theorems on product spaces, and as applications, three multiplicity results of non semi‐trivial solutions for (1.1) are obtained. Copyright © 2015 John Wiley & Sons, Ltd.     

A metric characterisation of compact plane retracts and applications

Summary For compact sets M R², investigating the problem of representing functions V: R² R⁺ in the form V(x)=(x, M), where is a suitable metric on R², a characterisation of retracts is obtained. As for applications, two results in topological dynamics are given.     

Time-Localization of Random Distributions on Wiener Space II: Convergence,Fractional Brownian Density Processes

For a random element X of a nuclear space of distributions on Wiener space C([0,1],R ^d ), the localization problem consists in projecting X at each time t[0,1] in order to define an S(R ^d )-valued process X={X(t),t[0,1]}, called the time-localization of X. The convergence problem consists in deriving weak convergence of time-localization processes (in C([0,1],S(R ^d )) in this paper) from weak convergence of the corresponding random distributions on C([0,1],R ^d ). Partial steps towards the solution of this problem were carried out in previous papers, the tightness having remained unsolved. In this paper we complete the solution of the convergence problem via an extension of the time-localization procedure. As an example, a fluctuation limit of a system of fractional Brownian motions yields a new class of S(R ^d )-valued Gaussian processes, the fractional Brownian density processes.     

Functions Without Exceptional Family of Elements and Complementarity Problems

In Ref. 1, Isac, Bulavski, and Kalashnikov introduced the concept of exceptional family of elements for a continuous function f: R ⁿR ⁿ. It is known that, if there does not exist an exceptional family of elements for f, then the corresponding complementarity problem has a solution. In this paper, we show that several classes of nonlinear functions, known in complementarity theory or other domains, are functions without exceptional family of elements and consequently the corresponding complementarity problem is solvable. It is evident that the notion of exceptional family of elements provides an alternative way of determining whether or not the complementarity problem has a solution.     

Rigidity theorem for harmonic maps from Riemannian manifold to Grassmannian manifold

We first study the Grassmannian manifoldG _n (R^n+p)as a submanifold in Euclidean space ⁿ (R ^n+p). Then we give a local expression for each map from Riemannian manifoldM toG ⁿ (R ^n+p) ⁿ (R ^n+p), and use the local expression to establish a formula which is satisfied by any harmonic map fromM toG _n (R ^n+p). As a consequence of this formula we get a rigidity theorem.     

Existence and multiplicity of positive solutions for semilinear elliptic systems with Sobolev critical exponents

In this paper, we study the existence and multiplicity of positive solutions to the following system , in Ω; u,v>0 in Ω; and u=v=0 on ∂Ω, where Ω is a bounded smooth domain in R^N; FC¹((R⁺)²,R⁺) is positively homogeneous of degree μ; ; and ε is a positive parameter. Using sub–supersolution method, we prove the existence of positive solutions for the above problem. By means of the variational approach, we prove the multiplicity of positive solutions for the above problem with μ(2,2^*].     

Global minimization of large-scale constrained concave quadratic problems by separable programming

The global minimization of a large-scale linearly constrained concave quadratic problem is considered. The concave quadratic part of the objective function is given in terms of the nonlinear variablesx R ⁿ , while the linear part is in terms ofy R ^k. For large-scale problems we may havek much larger thann. The original problem is reduced to an equivalent separable problem by solving a multiple-cost-row linear program with 2n cost rows. The solution of one additional linear program gives an incumbent vertex which is a candidate for the global minimum, and also gives a bound on the relative error in the function value of this incumbent. Ana priori bound on this relative error is obtained, which is shown to be 0.25, in important cases. If the incumbent is not a satisfactory approximation to the global minimum, a guaranteed-approximate solution is obtained by solving a single liner zero–one mixed integer programming problem. This integer problem is formulated by a simple piecewise-linear underestimation of the separable problem.This research was supported by the Division of Computer Research, National Science Foundation under Research Grant DCR8405489.Dedicated to Professor George Dantzig in honor of his 70th Birthday.     

A class of nonlinear complementarity problems for multifunctions

Given a continuous mapF:R ⁿ R ⁿ and a lower semicontinuous positively homogeneous convex functionh:R ⁿ R, the nonlinear complementarity problem considered here is to findxR ₊ ⁿ andyh(x), the subdifferential ofh atx, such thatF(x)+y0 andx ^T (F(x)+y)=0. Some existence theorems for the above problem are given under certain conditions on the mapF. An application to quasidifferentiable convex programming is also shown.The authors are grateful to Professor O. L. Mangasarian and the referee for their substantive suggestions.     

Global Existence of Solutions for the Cauchy Problem of the Kawahara Equation with L 2 Initial Data

In this paper we study solvability of the Cauchy problem of the Kawahara equation 偏导dtu ＋ au偏导dzu ＋ β偏导d^3xu ＋γ偏导d^5xu = 0 with L^2 initial data. By working on the Bourgain space X^r,s（R^2） associated with this equation, we prove that the Cauchy problem of the Kawahara equation is locally solvable if initial data belong to H^r（R） and -1 〈 r ≤ 0. This result combined with the energy conservation law of the Kawahara equation yields that global solutions exist if initial data belong to L^2（R）.     

On the well-posedness of the Schrödinger-Korteweg-de Vries system

We prove that the Cauchy problem for the Schrödinger-Korteweg-de Vries system is locally well-posed for the initial data belonging to the Sobolev spaces L²(R)×H−3/4(R), and Hs(R)×H−3/4(R) (s>−1/16) for the resonant case. The new ingredient is that we use the -type space, introduced by the first author in Guo (2009) [10], to deal with the KdV part of the system and the coupling terms. In order to overcome the difficulty caused by the lack of scaling invariance, we prove uniform estimates for the multiplier. This result improves the previous one by Corcho and Linares (2007) [6].     

Summability Kernels for <Emphasis Type="Italic">L</Emphasis><Superscript><Emphasis Type="Italic">p</Emphasis></Superscript> Multipliers

In this article we study the problem of extending Fourier Multipliers on L ^p (T) to those on L ^p (R) by taking convolution with a kernel, called a summability kernel. We characterize the space of such kernels for the cases p = 1 and p = 2. For other values of p we give a necessary condition for a function to be a summability kernel. For the case p = 1, we present properties of measures which are transferred from M(T) to M(R) by summability kernels. Furthermore it is shown that every l _p sequence can be extended to some L ^q (R) multipliers for certain values of p and q.     

Surrogate methods for linear inequalities

Three algorithms are developed and validated for finding a pointx inR ⁿ that satisfies a given system of inequalities,Axb. A andb are a given matrix and a given vector inR ^m×n andR ^m , respectively, with the rows ofA assumed normalized. The algorithms are iterative and are based upon the orthogonal projection of an infeasible point onto the manifold of the bounding hyperplanes of some of the given constraints. The choice of the active constraints and the actual projection are accomplished through the use of surrogate constraints.This work was supported in part by the City University of New York Research Center. The author thanks Professor D. Goldfarb for suggesting the problem and also for his valuable literature information and time. The word surrogate was borrowed from one of his works.     

Inviscid limit for the energy-critical complex Ginzburg-Landau equation

In this paper, we consider the limit behavior for the solution of the Cauchy problem of the energy-critical complex Ginzburg-Landau equation in Rn, n?3. In lower dimension case (3?n?6), we show that its solution converges to that of the energy-critical nonlinear Schrödinger equation in , T>0, s=0,1, as a by-product, we get the regularity of solutions in H³ for the nonlinear Schrödinger equation. In higher dimension case (n>6), we get the similar convergent behavior in C(0,T,L²(Rn)). In both cases we obtain the optimal convergent rate.     

Local solvability of a nonstationary leakage problem for an ideal incompressible fluid, 3

In this paper we prove the existence and uniqueness of solutions of the leakage problem for the Euler equations in bounded domain Ω C R³ with corners π/n, n = 2, 3… We consider the case where the tangent components of the vorticity vector are given on the part S₁ of the boundary where the fluid enters the domain. We prove the existence of an unique solution in the Sobolev space W_p^l(Ω), for arbitrary natural l and p > 1. The proof is divided on three parts: (1) the existence of solutions of the elliptic problem in the domain with corners where v – velocity vector, ω – vorticity vector and n is an unit outward vector normal to the boundary, (2) the existence of solutions of the following evolution problem for given velocity vector (3) the method of successive approximations, using solvability of problems (1) and (2).     

Some problems of vector analysis and generalized formulations of boundary-value problems for the Navier-Stokes equations

We consider the problem of finding the restrictions on the domain R ⁿ,n=2,3, under which the space of the solenoidal vector fields from coincides with the space, the closure in W ₂ ¹ () of the set of all solenoidal vectors from. We give domains Rⁿ, for which the factor space has a finite nonzero dimension. A similar problem is considered for the spaces of solenoidal vectors with a finite Dirichlet integral. Based on this, one compares two generalized formulations of boundary-value problems for the Stokes and Navier-Stokes systems. The following auxiliary problems are studied:,.Dedicated to J. Leray on his 70th anniversary.Translated from Zapiski Nauchnykh Seminarov Leningradskogo Otdeleniya Matematicheskogo Instituta im. V. A. Steklova AN SSSR, Vol. 59, pp. 81–116, 1976.     

The class of solenoidal planar-helical vector fields

The class of solenoidal vector fields whose lines lie in planes parallel to R ² is constructed by the method of mappings. This class exhausts the set of all smooth planarhelical solutions of Gromeka’s problem in some domain D ? R ³. In the case of domains D with cylindrical boundaries whose generators are orthogonal to R ², it is shown that the choice of a specific solution from the constructed class is reduced to the Dirichlet problem with respect to two functions that are harmonic conjugates in D ² = D∩R ²; i.e., Gromeka’s nonlinear problem is reduced to linear boundary value problems. As an example, a specific solution of the problem for an axisymmetric layer is presented. The solution is based on solving Dirichlet problems in the form of series uniformly convergent in \(\bar D^2\) in terms of wavelet systems that form bases of various spaces of functions harmonic in D ².     

Solutions of a class of Hamiltonian elliptic systems in

We study the existence of ground state solutions for the following elliptic systems in R^N

where b=(b₁,…,b_N) is a constant vector and HC¹(R^N×R²,R) is nonperiodic in variables x and super-quadratic as |z|→∞. By a recent critical point theorem for strongly indefinite problem, we obtain the existence of at least one ground state solution.