Structured Pseudospectra Of Block Matrices

In this thesis,we consider the question of equivalence of pseudospectra and structured pseu-dospectra of block matrices.The structures we mainly considered are called double structures.That is,the internal blocks of the given matrix are of the same structure as the block matrix.We mainly solve the open problem which was put forward by R.Ferro,American scholar and J.A.Virtanen,British scholar.