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91.
92.
B. P. Duggal 《Proceedings of the American Mathematical Society》2001,129(1):83-87
Given , the algebra of operators on a Hilbert space , define and by and . Let and be two classes of operators strictly larger than the class of normal operators. Define (resp., if (resp., for all and . This note shows that the equivalence holds for a number of the commonly considered classes of operators.
93.
ℓ<Subscript><Emphasis Type="Italic">p</Emphasis></Subscript>-Diagonally Dominant Symmetric Operators
The existence of p-universal diagonally dominant symmetric liner operators on separable Hilbert spaces is discussed. Also, properties of these operators and their characterization in terms of their spectra are investigated. 相似文献
94.
Mai Lu Zhide Hu Zheng Yang Fulin Wei 《International Journal of Infrared and Millimeter Waves》2000,21(6):965-977
In this paper, the electric field lines of the dominant mode in a closed V-groove guide as well as an open one are analysed by finite element method. The results show that the electric field lines are not parallel to the parallel plate region, but perpendicular to them. Since the attenuation increase with increasing frequency when the electric field lines are perpendicular to the mental walls, the V-groove is not suitable to be used in millimeter and submillimeter wavebands, and it is can't be regarded as low-loss wave guiding structures. 相似文献
95.
96.
Taussky定理推广与应用 总被引:3,自引:1,他引:2
本文在Cassini卵形域上推广了Taussky定理。所得结果修正了Brauer定理,作为应用给出不可约双对角占优矩阵非奇异的充要条件,最后把基本结果推广到分块矩阵上。 相似文献
97.
We consider some models of classical statistical mechanics which admit an investigation by means of the theory of dominant ground states. Our models are related to the Gibbs ensemble for the multidimensional SOS model with symmetric constraints
x
m/2. The main result is that for 0, where 0 does not depend onm, the structure of thermodynamic phases in the model is determined by dominant ground states: for an evenm a Gibbs state is unique and for an oddm the number of space-periodic pure Gibbs states is two. 相似文献
98.
J. X. Zhou 《Journal of Optimization Theory and Applications》1994,80(2):333-347
Let be an irreflexive (strict) binary relation on a nonempty setX. Denote the completion of by , i.e.,yx ifxy does not hold. An elementx
*
X is said to be a maximal element of onX ifx
*
x, xX. In this paper, an extension of the Zorn lemma to general nontrasitive binary relations (may lack antisymmetry) is established and is applied to prove existence of maximal elements for general nontrasitive (reflexive or irreflexive) binary relations on nonempty sets without assuming any topological conditions or linear structures. A necessary and sufficient condition has been also established to completely characterize the existence of maximal elements for general irreflexive nontrasitive binary relations. This is the first such result available in the literature to the best of our knowledge. Many recent known existence sults in the literature for vector optimization are shown to be special cases of our result.This work was supported in part by AFSOR Grant 91-0097.The author is grateful to the referees and Professor P. L. Yu for their comments and suggestions that led to this improved paper. 相似文献
99.
For the SOS model defined by the Hamiltonian
, where
x
,
x
,{1,2,...},h>0,x
d
,d2 it is shown that in the low-temperature region an infinite sequence of first-order phase transitions takes place whenh»0 and the temperature is fixed. 相似文献
100.
具非零元素链二重几何平均对角占优矩阵 总被引:6,自引:0,他引:6
本文引进了具非零元素链二重几何平均对角占优矩阵的概念,讨论了它的性质及其与具非零元素链对角占优矩阵,非奇H-矩阵等的关系 相似文献