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排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
992.
Two new least-squares mixed finite element procedures are formulated for solving convection-dominated Sobolev equations. Optimal
H(div;Ω)×H
1(Ω) norms error estimates are derived under the standard mixed finite spaces. Moreover, these two schemes provide the approximate
solutions with first-order and second-order accuracy in time increment, respectively. 相似文献
993.
The boundedness of multilinear singular integrals of Calderón-Zygmund type on product of variable exponent Lebesgue spaces
over both bounded and unbounded domains are obtained. Further more, the boundedness for this type multilinear operators on
product of variable exponent Morrey spaces over domains is shown in the paper. 相似文献
994.
In this paper, the qualitative properties of general nonautonomous Lotka-Volterra n-species competitive systems with impulsive effects are studied. Some new criteria on the permanence, extinction and global
attractivity of partial species are established by used the methods of inequalities estimate and Liapunov functions. As applications,
nonautonomous two species Lotka-Volterra systems with impulses are discussed. 相似文献
995.
We propose a new way of rewriting the two dimensional Euler equations and derive an original canonical characteristic relation
based on the characteristic theory of hyperbolic systems. This relation contains the derivatives strictly along the bicharacteristic
directions, and can be viewed as the 2D extension of the characteristic relation in 1D case. 相似文献
996.
This paper is devoted to studying the commutators of the multilinear singular integral operators with the non-smooth kernels
and the weighted Lipschitz functions. Some mapping properties for two types of commutators on the weighted Lebesgue spaces,
which extend and generalize some previous results, are obtained. 相似文献
997.
This paper considers the semi-resumable model of single machine scheduling with a non-availability period. The machine is
not available for processing during a given time interval. A job cannot be completed before the non-availability period will
have to partially restart after the machine has become available again. For the problem with objective of minimizing makespan,
the tight worst-case ratio of algorithm LPT is given, and an FPTAS is also proposed. For the problem with objective of minimizing total weighted completion time, an
approximation algorithm with worst-case ratio smaller than 2 is presented. Two special cases of the latter problem are also
considered, and improved algorithms are given. 相似文献
998.
This paper concerns optimal investment problem with proportional transaction costs and finite time horizon based on exponential
utility function. Using a partial differential equation approach, we reveal that the problem is equivalent to a parabolic
double obstacle problem involving two free boundaries that correspond to the optimal buying and selling policies. Numerical
examples are obtained by the binomial method. 相似文献
999.
In this paper, the extremum of second-order directional derivatives, i.e. the gradient of first-order derivatives is discussed.
Given second-order directional derivatives in three nonparallel directions, or given second-order directional derivatives
and mixed directional derivatives in two nonparallel directions, the formulae for the extremum of second-order directional
derivatives are derived, and the directions corresponding to maximum and minimum are perpendicular to each other. 相似文献
1000.