7 papers
Spectrum and Fine Spectrum of Band Matrices Generated by Oscillatory Sequences
Jyoti Rani, Arnab Patra, P D Srivastava
In this paper, a new class of band matrices is considered where the entries of each non-zero band form a sequence with two limit points. The compact perturbation technique is used…
Spectrum and fine spectrum of generalised lower triangular triple band matrices over the sequence space
Arnab Patra, P. D. Srivastava
The spectrum of triangular band matrices defined on the sequence spaces where the entries of each band is a constant or convergent sequence is well studied. In this article, the sp…
On some study of the fine spectra of generalized difference operator on
Riddhick Birbonshi, Arnab Patra, P. D. Srivastava
In this paper, we determine the spectrum, the point spectrum, the continuous spectrum and the residual spectrum of the generalized difference operator on the sequence spa…
Spectra of the lower triangular matrix over
Sanjay Kumar Mahto, Arnab Patra, P. D. Srivastava
The spectra and fine spectra of the lower triangular matrix over the sequence space are determined. The diagonal and s…
A note on Anderson's theorem in the infinite-dimensional setting
Riddhick Birbonshi, Ilya M. Spitkovsky, P. D. Srivastava
Anderson's theorem states that if the numerical range W(A) of an n-by-n matrix A is contained in the unit disk and intersects with the unit circle at more than n points, then it co…
On the boundary of the numerical range of some Jacobi operators
R. Birbonshi, A. Patra, P. D. Srivastava
In this paper, we study the numerical range of Jacobi operators and it is shown that under certain conditions, the boundary of the numerical range of these operators can be non-rou…
On some study of the Fine Spectra of -th band triangular matrices
R. Birbonshi, P. D. Srivastava
It has been observed that for the 2nd and 3rd band lower triangular matrices and , only the boundary of the spectrum gives the continuous spectrum while the rest…