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971.
Wu Jiongqi 《Annals of Differential Equations》2005,21(4):592-597
In this paper N-dimensional singular, p-Laplace equations of the following form are considered, where p ≥N, β > 0, and f : [0,∞)×(0,∞)×[0, ∞)→[0,∞) is a continuous function. Some sufficient conditions are obtained for the existence of infinitely many radially positive entire solutions of the equation which are asymptotic to positive constant multiples of |x|(p-N)/(p-1) for p > N or log|x| for N = p as |x|→∞. 相似文献
972.
Coexistence states for systems of mutualist species 总被引:1,自引:0,他引:1
Zongming Guo 《Journal of Mathematical Analysis and Applications》2005,303(1):61-80
Coexistence states for a class of systems of mutualist species are obtained via bifurcation theory and monotone techniques. 相似文献
973.
Nils Ackermann 《Journal of Functional Analysis》2006,234(2):277-320
In an abstract setting we prove a nonlinear superposition principle for zeros of equivariant vector fields that are asymptotically additive in a well-defined sense. This result is used to obtain multibump solutions for two basic types of periodic stationary Schrödinger equations with superlinear nonlinearity. The nonlinear term may be of convolution type. If the superquadratic term in the energy functional is convex, our results also apply in certain cases if 0 is in a gap of the spectrum of the Schrödinger operator. 相似文献
974.
The time-optimal control of rigid-body angular rates is investigated in the absence of direct control over one of the angular velocity components. The existence of singular subarcs in the time-optimal trajectories is explored. A numerical survey of the optimality conditions reveals that, over a large range of boundary conditions, there are in general several distinct extremal solutions. A classification of extremal solutions is presented, and domains of existence of the extremal subfamilies are established in a reduced parameter space. A locus of Darboux points is obtained, and global optimality of the extremal solutions is observed in relation to the Darboux points. The continuous dependence of the optimal trajectories with respect to variations in control constraints is noted, and a procedure to obtain the time-optimal bang-bang solutions is presented.This work was supported in part by DARPA under Contract No. ACMP-F49620-87-C-0016, by SDIO/IST under Contract No. F49620-87-C0088, and by Air Force Grant AFOSR-89-0001. 相似文献
975.
Yan Zuomao 《Annals of Differential Equations》2008,(3):361-366
In this paper, using the theory of resolvent operators, Banach,s contraction prin-ciple and Schauder,s fixed point theorem, we study the existence of integral solutions to semilinear integrodifferential equations under nonlocal conditions in Banach space. An example is provided to illustrate the results obtained. 相似文献
976.
We consider piecewise smooth viscosity solutions to a Hamilton-Jacobi equation, for which the Hamiltonian is the maximum of
a finite number of smooth concave functions. We describe the possible types of “basic” singularities, namely jump discontinuities
in either the derivative of the solution or the Hamiltonian, which occur across a smooth hypersurface. Each such type of singularity
is described in terms of the properties of the Hamiltonian and the classical characteristics in the regions on either side
of the singularity. Where appropriate, singular characteristic equations of the types developed by Melikyan are formulated
which can be used in constructions. 相似文献
977.
Jing Wang 《Journal of Mathematical Analysis and Applications》2008,346(1):314-326
We consider a one-dimensional radiation hydrodynamics model in the case of the equilibrium diffusion approximation which is described by the compressible Navier-Stokes system with the additional terms in the pressure and internal energy respectively, which embody the effect of radiation. Under the physical growth conditions on the heat conductivity, we establish the existence and uniqueness of strong solutions to the Cauchy problem with large initial data, where the initial density and velocity may have differing constant states at infinity. Moreover, we show that if there is no vacuum in the initial density, then, the vacuum and concentration of the density will never occur in any finite time. 相似文献
978.
Francisco Odair de Paiva Eugenio Massa 《Journal of Mathematical Analysis and Applications》2008,342(1):638-650
We consider the Dirichlet problem for the equation −Δu=λu±f(x,u)+h(x) in a bounded domain, where f has a sublinear growth and h∈L2. We find suitable conditions on f and h in order to have at least two solutions for λ near to an eigenvalue of −Δ. A typical example to which our results apply is when f(x,u) behaves at infinity like a(x)|u|q−2u, with M>a(x)>δ>0, and 1<q<2. 相似文献
979.
In this paper, a graphical characterization, in the decision space, of the properly efficient solutions of a convex multiobjective
problem is derived. This characterization takes into account the relative position of the gradients of the objective functions
and the active constraints at the given feasible solution. The unconstrained case with two objective functions and with any
number of functions and the general constrained case are studied separately. In some cases, these results can provide a visualization
of the efficient set, for problems with two or three variables. Besides, a proper efficiency test for general convex multiobjective
problems is derived, which consists of solving a single linear optimization problem. 相似文献
980.
We consider a spatial interaction model for locating a set of new facilities that compete for customer demand with each other, as well as with some pre-existing facilities to capture the “market expansion” and the “market cannibalization” effects. Customer demand is assumed to be a concave non-decreasing function of the total utility derived by each customer from the service offered by the facilities. The problem is formulated as a non-linear Knapsack problem, for which we develop a novel solution approach based on constructing an efficient piecewise linear approximation scheme for the objective function. This allows us to develop exact and α-optimal solution approaches capable of dealing with relatively large-scale instances of the model. We also develop a fast Heuristic Algorithm for which a tight worst-case error bound is established. 相似文献