THE ABSENCE OF SINGULAR CONTINUOUS SPECTRUM FOR PERTURBED JACOBI OPERATORS

This paper is mainly about the spectral properties of a class of Jacobi operators(H_(c,b)u)(n)=c_(n)u(n+1)+c_(n-1)u(n-1)+b_(n)u(n),.where∣c_(n)−1∣=O(n^(−α))and b_(n)=O(n^(−1)).We will show that,forα≥1,the singular continuous spectrum of the operator is empty.

Manifolds with Special Commuting Jacobi Operators

For a Riemannian manifold（Mn,g） with curvature tensor R,the Jacobi operator J（X） is give.In this paper,the flat Riemannian manifolds are characterized in terms of special commutation properties of their Jacobi operators.

Global structure of spectra of periodic non-Hermitian Jacobi operators

We give global structure of spectra of periodic non-Hermitian Jacobi operators by the discriminant and its stationary points. We also give necessary and sufficient conditions for real spectra and single interval spectra.

Commuting Structure Jacobi Operator for Real Hypersurfaces in Complex Two-plane Grassmannians

We classify real hypersurfaces in complex two-plane Grassmannians whose structure Jacobi operator commutes either with any other Jacobi operator or with the normal Jacobi operator.

Weighted Approximation by Multidimensional Baskakov Operators

In this paper, we shall point out that the Multidimensional Baskakov opera- tors are unbounded in . Then we give a inverse theorems for multivariate Baskakov operators with Jacobi weights. A crucial tools in our approach is a decompo- sition technique and a new type weights norm and flew K-function