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排序方式: 共有4524条查询结果,搜索用时 12 毫秒
31.
B. F. Svaiter 《Proceedings of the American Mathematical Society》2003,131(12):3851-3859
Any maximal monotone operator can be characterized by a convex function. The family of such convex functions is invariant under a transformation connected with the Fenchel-Legendre conjugation. We prove that there exists a convex representation of the operator which is a fixed point of this conjugation.
32.
We consider an anisotropic phase‐field model for the isothermal solidification of a binary alloy due to Warren–Boettinger ( Acta. Metall. Mater. 1995; 43 (2):689). Existence of weak solutions is established under a certain convexity condition on the strongly non‐linear second‐order anisotropic operator and Lipschitz and boundedness assumptions for the non‐linearities. A maximum principle holds that guarantees the existence of a solution under physical assumptions on the non‐linearities. The qualitative properties of the solutions are illustrated by a numerical example. Copyright © 2003 John Wiley & Sons, Ltd. 相似文献
33.
两相同部件温贮备可修的人机系统解的性质分析 总被引:4,自引:1,他引:4
郭卫华 《数学的实践与认识》2003,33(7):88-95
本文首先用强连续算子半群理论证明了两相同部件温贮备可修的人机系统动态非负解的存在唯一性 ,然后证明了 0是系统主算子的本征值 ,并得到 0本征值对应的本征向量是正的 ,从而系统存在稳态正解 . 相似文献
34.
Alain Joye 《Journal of statistical physics》1994,75(5-6):929-952
The spectrum of the Floquet operator associated with time-periodic perturbations of discrete Hamiltonians is considered. If the gap between successive eigenvalues
j
of the unperturbed Hamiltonian grows as
j
-
j-1
j
and the multiplicity of
j
grows asj
with >0 asj tends to infinity, then the corresponding Floquet operator possesses no absolutely continuous spectrum provided the perturbation is smooth enough. 相似文献
35.
We study a semigroup of linear operators on a Banach space X which satisfies the condition codim X
0<, where
We show that X
0 is closed and establish some properties of the asymptotic behavior of the subspaces complementing X
0 to X. 相似文献
36.
T. Ehrhardt 《Acta Mathematica Hungarica》2003,99(3):233-262
We give another proof of the Szeg\H{o}–Widom Limit Theorem. This proof relies on a new Banach algebra method that can be directly
applied to the asymptotic computation of the Toeplitz determinants. As a by-product, we establish an interesting identity
for operator determinants of Toeplitz operators, namely if
are certain matrix valued functions defined on the unit circle, then
This revised version was published online in June 2006 with corrections to the Cover Date. 相似文献
37.
This paper deals with the solvability of boundary value problems for singular integral equations of the form (i)-(ii).By an algebraic method we reduce the problem (i)-(ii) to a system of linear algebraic equations which gives all solutions in a closed form.AMS Subject Classification: 47G05, 45GO5, 45E05 相似文献
38.
《Acta Mathematica Hungarica》2003,100(1-2):1
A symmetric operator X^ is attached to each operator X that leaves the domain of a given positive operator A invariant and makes the product AX symmetric. Some spectral properties of X^ are derived from those of X and, as a consequence, various conditions ensuring positivity of products of the form AX
1 ... X
n are proved. The question of ^-complete positivity of the mapping p → Ap(X
1,...,X
n) defined on complex polynomials in n variables is investigated. It is shown that the set ω is related to the McIntosh-Pryde
joint spectrum of (X
1,...,X
n) in case all the operators A, X
1,...,X
n are bounded. Examples illustrating the theme of the paper are included.
This revised version was published online in June 2006 with corrections to the Cover Date. 相似文献
39.
Mathematical Notes - 相似文献
40.
It is shown that a Korovkin type theorem for a sequence of linear positive operators acting in weighted space L
p,w
(loc) does not hold in all this space and is satisfied only on some subspace. 相似文献