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931.
S. V. Astashkin 《Functional Analysis and Its Applications》2003,37(3):221-224
Using new extrapolation estimates for the
- and
-functionals of couples of limit spaces of the
-scale
, we introduce a class of extrapolation functors. A characterization of this class via the real interpolation method permits one to obtain new equivalent expressions for the norms in symmetric spaces close to
and
, which depend only on the
-norms of a function. 相似文献
932.
Evgeny AbakumovAlexander Borichev 《Journal of Functional Analysis》2002,188(1):1-26
We construct right shift invariant subspaces of index n, 1?n?∞, in ?p spaces, 2<p<∞, and in weighted ?p spaces. 相似文献
933.
K. A. Volosov 《Mathematical Notes》2002,71(3-4):339-354
By using the recently discovered new invariant properties of the ansatz of R. Hirota's method, we prove that the classes of linear fractional solutions to some nonlinear equations are closed. This allows us to construct new solutions for a chosen class of dissipative equations. This algorithm is similar to the method of dressing the solutions of integrable equations. The equations thus obtained imply a compatibility condition and are known as a nonlinear Lax pair with variable coefficients. So we propose a method for constructing such pairs. To construct solutions of a more complicated form, we propose to use the property of zero denominators and factorized brackets, which has been discovered experimentally. The expressions thus constructed are said to be quasi-invariant. They allow us to find true relations between the functions contained in the ansatz, to correct the ansatz, and to construct a solution. We present some examples of new solutions constructed following this approach. Such solutions can be used for majorizing in comparison theorems and for modeling phase processes and process in neurocomputers. A program for computing solutions by methods of computer algebra is written. These techniques supplement the classical methods for constructing solutions by using their group properties. 相似文献
934.
This paper studies a facility location problem with stochastic customer demand and immobile servers. Motivated by applications to locating bank automated teller machines (ATMs) or Internet mirror sites, these models are developed for situations in which immobile service facilities are congested by stochastic demand originating from nearby customer locations. Customers are assumed to visit the closest open facility. The objective of this problem is to minimize customers' total traveling cost and waiting cost. In addition, there is a restriction on the number of facilities that may be opened and an upper bound on the allowable expected waiting time at a facility. Three heuristic algorithms are developed, including a greedy-dropping procedure, a tabu search approach and an -optimal branch-and-bound method. These methods are compared computationally on a bank location data set from Amherst, New York. 相似文献
935.
Let A be a separable simple C*-algebra. For each ;) on A such that π(a) has a non-trivial invariant subspace in Hπ. 相似文献
936.
This paper concerns a Markov operator T on a space L1, and aMarkov process P which defines a Markov operator on a spaceM of finite signed measures. For T, the paper presents necessaryand sufficient conditions for:
- a the existence of invariant probabilitydensities (IPDs)
- b the existence of strictly positive IPDs,and
- c the existence and uniqueness of IPDs.
- b the existence of strictly positive IPDs,and
937.
Let A, B be positive operators on a Hilbert space, z any complex number, m any positive integer, and
any unitarily invariant norm. We show that
and
Some related inequalities are also obtained. 相似文献
938.
Qingtang Jiang 《Proceedings of the American Mathematical Society》1998,126(2):561-567
Let be the wideband ambiguity function. It is obtained in this note that is -invariant if and only if the Fourier transform of is a Laguerre function.
939.
Danko R. Jocic 《Proceedings of the American Mathematical Society》1998,126(9):2705-2711
The Cauchy-Schwarz norm inequality for normal elementary operators
implies a means inequality for generalized normal derivations
for all , as well as an inequality for normal contractions and
for all in and for all unitarily invariant norms
940.
Piotr Pawlowski 《Transactions of the American Mathematical Society》1998,350(11):4461-4472
If is univariate polynomial with complex coefficients having all its zeros inside the closed unit disk, then the Gauss-Lucas theorem states that all zeros of lie in the same disk. We study the following question: what is the maximum distance from the arithmetic mean of all zeros of to a nearest zero of ? We obtain bounds for this distance depending on degree. We also show that this distance is equal to for polynomials of degree 3 and polynomials with real zeros.