Spectra and fine spectra for factorable matrices (Q814367)

A lower triangular matrix \(A = (a_{nk})\) is said to be factorable if \(a_{nk} = (a_n) (b_k)\). In this paper, the authors study mainly a subclass of the factorable matrices and prove a number of theorems on the spectra and fine spectra of such matrices. From their theorems, they deduce as special cases results that improve upon some results proved by the same authors separately over the years. They also study factorable conull matrices and obtain results on some generalized Cesàro matrices and on terraced matrices as well.