If $ M_ {C}=\left (\begin {smallmatrix} A&C0&B\end {smallmatrix}\right) $ is a $2\times 2$
upper triangular matrix on the Hilbert space $ H\oplus K $, then $ a $-Weyl's theorem for $ A …

When A∈ B (H1), B∈ B (H2) and C∈ B (H3) are given, we denote by M (D, E, F) an
operator, acting on the Hilbert space H1H2H3, of the form M (D, E, F)=. In this paper, we give …

Let σab (T)={λ∈ C: T-λIisnotanuppersemi-Fredholmoperatorwithfiniteascent} be the Browder
essential approximate point spectrum of T∈ B (H) and let σd (T)={λ∈ C: T-λIisnotsurjective} …

Abstract “Weyl's theorem holds” for an operator when the complement in the spectrum of the
“Weyl” spectrum” coincides with the isolated points of the spectrum which are eigenvalues of …

Let ℋ and\cal KK be complex infinite dimensional separable Hilbert spaces. We denote by
M_C=\left () MC=(AC 0 B) a 2× 2 upper triangular operator matrix acting on\cal H ⊕\cal K …

Abstract When A∈ B (H) and B∈ B (K) are given, we denote by MC an operator acting on
the Hilbert space H⊕ K of the form M_ C=\left (. In this paper, first we give the necessary and …

In this paper it is shown that if $ M_ {C}=\left (\begin {smallmatrix} A&C 0&B\end
{smallmatrix}\right) $ is a $2\times 2$ upper triangular operator matrix acting on the Hilbert …

Let and be infinite dimensional separable complex Hilbert spaces and T a bounded linear
operator on.'Weyl's theorem'holds for operator T when the complement in the spectrum of …

Abstract Let MC=(AC 0 B) be an upper triangular operator matrix on the Hilbert space H⊕ H,
where H is a Hilbert space. In this paper, necessary and sufficient conditions for σ⁎(MC) …

A Banach space operator T∈ B (χ) is polaroid if points λ∈ iso σ (T) are poles of the
resolvent of T. Let\sigma_a (T),\sigma_w (T), aw (T), SF_+(T)\, and\, SF_-(T) denote …