We extend the recent stability results of Ambrozie for Fredholm essential complexes to the semi-Fredholm case. Let X,Y be Banach spaces. By an operator we always mean a bounded linear operator. The set of all operators from X to Y will be denoted by L(X,Y ). Denote by N(T ) and R(T ) the kernel and range of an operator T ∈ L(X, Y ). Recall that an operator T : X → Y is called semi-Fredholm if i...

A Banach space operator T ∈ B(X ) is polaroid if points λ ∈ isoσσ(T ) are poles of the resolvent of T . Let σa(T ), σw(T ), σaw(T ), σSF+(T ) and σSF−(T ) denote, respectively, the approximate point, the Weyl, the Weyl essential approximate, the upper semi–Fredholm and lower semi–Fredholm spectrum of T . For A, B and C ∈ B(X ), let MC denote the operator matrix (

Let 7(S) denote the reduced minimum modulus of a linear operator S acting in a complex Banach space X, and let / denote the identity on X. In this paper it is shown that for a (not necessarily bounded) Fredholm operator T acting in X, the limit lim y^fy/rt exists and is equal to the supremum of all positive numbers S such that the dimension of the null space and the codimension of the range of ...

‎in this paper we try to extend geometric concepts in the context of operator valued tensors‎. ‎to this end‎, ‎we aim to replace the field of scalars $ mathbb{r} $ by self-adjoint elements of a commutative $ c^star $-algebra‎, ‎and reach an appropriate generalization of geometrical concepts on manifolds‎. ‎first‎, ‎we put forward the concept of operator-valued tensors and extend semi-riemannian...

in this paper, we introduce and study the concept of $r$-fuzzy regular semi open (closed) sets in smooth topological spaces. by using $r$-fuzzy regular semi open (closed) sets, we define a new fuzzy closure operator namely $r$-fuzzy regular semi interior (closure) operator. also, we introduce fuzzy regular semi continuous and fuzzy regular semi irresolute mappings. moreover, we investigate the ...

This paper deals with a semi-classical limit(Theorem 1) by using traditional mathematical methods, and shows a Hopf theorem as a corollary. A formal discussing of it may be found in [7] 1 A semi-classical limit theorem Let M be a compact, closed Riemannian manifold of dim n, and V a vector field without degenerate zeros on M . Let Λ∗(M) be the space of differential forms on M , and D = d+ δ : Λ...

In this paper, we introduce and study the concept of $r$-fuzzy regular semi open (closed) sets in smooth topological spaces. By using $r$-fuzzy regular semi open (closed) sets, we define a new fuzzy closure operator namely $r$-fuzzy regular semi interior (closure) operator. Also, we introduce fuzzy regular semi continuous and fuzzy regular semi irresolute mappings. Moreover, we investigate the ...

The aim of this paper is to provide new upper bounds ω(T), which denotes the numerical radius a bounded operator T on Hilbert space (H,⟨·,·⟩). We show Aczél inequality in terms |T|. Next, we give certain inequalities about A-numerical ωA(T) and A-operator seminorm ∥T∥A an T. also present several results related 2×2 block matrices semi-Hilbert operators, by using symmetric matrices.