Property (R) for Bounded Linear Operators

We introduce the spectral property (R), for bounded linear operators defined on a Banach space, which is related to Weyl type theorems. This property is also studied in the framework of polaroid, or left polaroid, operators.     

Polaroid type operators under quasi-affinities

In this paper we study the preservation of some polaroid conditions under quasi-affinities. As a consequence, we derive several results concerning the preservation of Weyl type theorems and generalized Weyl type theorems under quasi-affinities.     

SVEP and Generalized Weyl’s Theorem

We use localised single-valued extension property to prove generalized Weyl/Browder and a-generalized Weyl/Browder type theorems for Banach space operators.     

A Unifying Approach to Weyl Type Theorems for Banach Space Operators

Weyl type theorems have been proved for a considerably large number of classes of operators. In this paper, by introducing the class of quasi totally hereditarily normaloid operators, we obtain a theoretical and general framework from which Weyl type theorems may be promptly established for many of these classes of operators. This framework also entails Weyl type theorems for perturbations f(T + K), where K is algebraic and commutes with T, and f is an analytic function, defined on an open neighborhood of the spectrum of T + K, such that f is non constant on each of the components of its domain.     

Coherent states,inverse mapping formula for Weyl transformations and application to equations of KdV type

In this paper, we consider the trace of generalized operators and inverse Weyl transformation. First of all we repeat the definition of test operators and generalized operators given in [18], denotingL ²(R) byH.     

Generalized Bernstein‐Kantorovich–type operators on a triangle

In this note, we construct generalized Bernstein‐Kantorovich–type operators on a triangle. The concern of this note is to present a Voronovskaja‐type and Grüss Voronovskaja‐type asymptotic theorems, and some estimates of the rate of approximation with the help of K‐functional, first and second order modulus of continuity. We also obtain Korovkin‐ and Voronovskaja‐type statistical approximation theorems via weighted mean matrix method. Lastly, we show that the numerical results which explain the validity of the theoretical results and the effectiveness of the constructed operators.     

The Local Spectral Properties of Extended Hamilton Operators

In this paper, we introduce the class of extended Hamilton operators and study various properties of this class. We examine the decomposability of extended Hamilton operators. In addition,we prove that an extended Hamilton operator with property(δ) is subscalar. Finally, we consider Weyl type theorems of this class.     

Property (gb) and perturbations

An operator T acting on a Banach space X possesses property (gb) if , where σa(T) is the approximate point spectrum of T, is the essential semi-B-Fredholm spectrum of T and π(T) is the set of all poles of the resolvent of T. In this paper we study property (gb) in connection with Weyl type theorems, which is analogous to generalized Browder?s theorem. Several sufficient and necessary conditions for which property (gb) holds are given. We also study the stability of property (gb) for a polaroid operator T acting on a Banach space, under perturbations by finite rank operators, by nilpotent operators and, more generally, by algebraic and Riesz operators commuting with T.     

Weyl numbers and eigenvalues of abstract summing operators

We estimate Weyl numbers and eigenvalues of operators via studying their abstract summing norms. In particular we prove estimates of these summing norms for abstract interpolation Lorentz spaces. For this we combine factorization theorems with estimates of concavity constants. Finally we apply our general eigenvalue results to integral operators with kernels of weakly singular type. We obtain asymptotically optimal estimates which extend the well-known classical results.     

On the Equivalence and Generalized of Weyl Theorem Weyl Theorem

We know that an operator T acting on a Banach space satisfying generalized Weyl＇s theorem also satisfies Weyl＇s theorem. Conversely we show that if all isolated eigenvalues of T are poles of its resolvent and if T satisfies Weyl＇s theorem, then it also satisfies generalized Weyl＇s theorem. We give also a sinlilar result for the equivalence of a-Weyl＇s theorem and generalized a-Weyl＇s theorem. Using these results, we study the case of polaroid operators, and in particular paranormal operators.     

Left cells in the weyl group of type 7

By applying an algorithm, we get a representative set of the left cells and all the left cell graphs for the Weyl group W of type E ₇,. From this, we see that the generalized r-invariants characterize all the non-exceptional left cells of W. We give a criterion to check the relation [Ltilde] on the elements in the exceptional left cells of W.     

Initial value problem for pseudo-differential operators

The algebra of generalized Weyl symbols is used in the proof of the continuity of the semigroupexptĤ in the Schwartz space of test functions. Fundamental results on algebras of differentiable Weyl symbols are presented. New examples of σ-temperate Riemannian metrics are constructed. Such metrics form a basis for construction of algebras of differentiable Weyl symbols. Conditions for the existence of semigroups of operators, conditions for pseudo-differential operators to be sectorial, and conditions for the continuity of such semigroups in spaces of test functions and distributions are established. Initial value problems for second-order differential operators are considered. Bibliography: 16 titles. Translated fromProblemy Matematicheskogo Analiza, No. 18, 1998, pp. 3–42.     

Browder’s Theorems through Localized SVEP

A bounded linear operator T ∈ L(X) on aBanach space X is said to satisfy “Browder’s theorem” if the Browder spectrum coincides with the Weyl spectrum. T ∈ L(X) is said to satisfy “a-Browder’s theorem” if the upper semi-Browder spectrum coincides with the approximate point Weyl spectrum. In this note we give several characterizations of operators satisfying these theorems. Most of these characterizations are obtained by using a localized version of the single-valued extension property of T. In the last part we shall give some characterizations of operators for which “Weyl’s theorem” holds.     

On the Functional Characterization of the Analytic Wave Front Set of an Hyperfunction

We give a characterization of d-dimensional modulation spaces with moderate weights by means of the d-dimensional Wilson basis. As an application we prove that pseudodifferential operators with generalized Weyl symbols are bounded on these modulation spaces.     

广义特征值的Wilkinson条件数

1．引言H．Weyl于1912年证明了下述结果［1］．Weyl定理．设人B为nxn．Hermite矩阵，特征值分别为入λl≥λ2≥…≥λn和以1三v2三…三on，那么人一nilsilA—Bll。，；＝l，2，…，。，其中11112为矩阵的谱范数。这条定理已成为矩阵扰动理论中的标准结果，被推广到奇异值问题、广义特征值问题、广义奇异值问题［2］，所得结果可通称为W6yl型定理，在矩阵分析和矩阵计算中有广泛而重要的应用．我们注意到，就实际应用而言，使用稳定算法而得到的计算结果的精度分析问题，可以转化为小扰动情形下的扰动分析．此时。B是A的某个邻近矩阵，而…     

Hemi-Continuous Operators and Some Applications

Existence theorems of generalized variational inequalities and generalized complementarity problems are obtained in topological vector spaces for hemi-continuous (respectively, strong hemi-continuous) operators. Fixed point theorems are also given in Hilbert spaces for set-valued operators T which are upper semicontinuous such that I - T are hemi-continuous (respectively, strong hemi-continuous).     

Markov Processes Related with Dunkl Operators

Dunkl operators are parameterized differential-difference operators on ^Nthat are related to finite reflection groups. They can be regarded as a generalization of partial derivatives and play a major role in the study of Calogero–Moser–Sutherland-type quantum many-body systems. Dunkl operators lead to generalizations of various analytic structures, like the Laplace operator, the Fourier transform, Hermite polynomials, and the heat semigroup. In this paper we investigate some probabilistic aspects of this theory in a systematic way. For this, we introduce a concept of homogeneity of Markov processes on ^Nthat generalizes the classical notion of processes with independent, stationary increments to the Dunkl setting. This includes analogues of Brownian motion and Cauchy processes. The generalizations of Brownian motion have the càdlàg property and form, after symmetrization with respect to the underlying reflection groups, diffusions on the Weyl chambers. A major part of the paper is devoted to the concept of modified moments of probability measures on ^Nin the Dunkl setting. This leads to several results for homogeneous Markov processes (in our extended setting), including martingale characterizations and limit theorems. Furthermore, relations to generalized Hermite polynomials, Appell systems, and Ornstein–Uhlenbeck processes are discussed.     

Semiseparable Integral Operators and Explicit Solution of an Inverse Problem for a Skew-Self-Adjoint Dirac-Type System

Inverse problem to recover the skew-self-adjoint Dirac-type system from the generalized Weyl matrix function is treated in the paper. Sufficient conditions under which the unique solution of the inverse problem exists, are formulated in terms of the Weyl function and a procedure to solve the inverse problem is given. The case of the generalized Weyl functions of the form f(l) exp{-2ilD}{\phi(\lambda)\,{\rm exp}\{-2i{\lambda}D\}}, where f{\phi} is a strictly proper rational matrix function and D = D* ≥ 0 is a diagonal matrix, is treated in greater detail. Explicit formulas for the inversion of the corresponding semiseparable integral operators and recovery of the Dirac-type system are obtained for this case.     

Left cells in weyl group of type E6

Let W be the Weyl group of type E₆, we use an algorithm of Shi to find a representative set of left cells in W. From these results, we can conclude that the generalized r -invariant determine completely the left cells.     

Relative Reduction and Buchberger’s Algorithm in Filtered Free Modules

In this paper we develop a relative Gröbner basis method for a wide class of filtered modules. Our general setting covers the cases of modules over rings of differential, difference, inversive difference and difference–differential operators, Weyl algebras and multiparameter twisted Weyl algebras (the last class of rings includes the classes of quantized Weyl algebras and twisted generalized Weyl algebras). In particular, we obtain a Buchberger-type algorithm for constructing relative Gröbner bases of filtered free modules.