scholarly journals On mixed C-semigroups of operators on Banach spaces

Filomat ◽  
2016 ◽  
Vol 30 (10) ◽  
pp. 2673-2682
Author(s):  
Masoud Mosallanezhad ◽  
Mohammad Janfada

In this paper an H-generalized Cauchy equation S(t+s)C = H(S(s),S(t)) is considered, where {S(t)}t?0 is a one parameter family of bounded linear operators and H : B(X) x B(X) ? B(X) is a function. In the special case, when H(S(s), S(t))=S(s)S(t)+D(S(s)-T(s))(S(t)-T(t)) with D ? B(X), solutions of H-generalized Cauchy equation are studied, where {T(t)}t?0 is a C-semigroup of operators. Also a similar equations are studied on C-cosine families and integrated C-semigroups.

1978 ◽  
Vol 84 (1) ◽  
pp. 131-142 ◽  
Author(s):  
M. Shearer

AbstractLet X, Y be real Banach spaces, and let = {f(λ):λ ∈ m} be an m-parameter family of bounded linear operators from X to Y, with f(λ) depending continuously on λ. The cases m = 1 and m = 2 are considered, and conditions on are found which determine the null space of f(λ) for all λ near a given λ0 such that f(λ0): X → Y is a Fredholm operator. The results obtained are shown to be of particular interest in perturbed bifurcation theory.


Author(s):  
A. El Amrani ◽  
A. Blali ◽  
J. Ettayb ◽  
M. Babahmed

In this paper, we introduce new classes of linear operators so called [Formula: see text]-groups, [Formula: see text]-groups and cosine families of bounded linear operators on non-archimedean Banach spaces over non-archimedean complete valued field [Formula: see text]. We show some results about it.


2010 ◽  
Vol 2010 ◽  
pp. 1-13
Author(s):  
M. Janfada

We introduce the notion of regularized quasi-semigroup of bounded linear operators on Banach spaces and its infinitesimal generator, as a generalization of regularized semigroups of operators. After some examples of such quasi-semigroups, the properties of this family of operators will be studied. Also some applications of regularized quasi-semigroups in the abstract evolution equations will be considered. Next some elementary perturbation results on regularized quasi-semigroups will be discussed.


2021 ◽  
Vol Accepted ◽  
Author(s):  
J. Ettayb ◽  
A. Blali ◽  
A. El amrani ◽  
R. A. Hassani

Author(s):  
Hans-Olav Tylli

Special operator-ideal approximation properties (APs) of Banach spaces are employed to solve the problem of whether the distance functions S ↦ dist(S*, I(F*, E*)) and S ↦ dist(S, I*(E, F)) are uniformly comparable in each space L(E, F) of bounded linear operators. Here, I*(E, F) = {S ∈ L(E, F) : S* ∈ I(F*, E*)} stands for the adjoint ideal of the closed operator ideal I for Banach spaces E and F. Counterexamples are obtained for many classical surjective or injective Banach operator ideals I by solving two resulting ‘asymmetry’ problems for these operator-ideal APs.


2016 ◽  
Vol 160 (3) ◽  
pp. 413-421 ◽  
Author(s):  
TOMASZ KANIA ◽  
NIELS JAKOB LAUSTSEN

AbstractA recent result of Leung (Proceedings of the American Mathematical Society, 2015) states that the Banach algebra ℬ(X) of bounded, linear operators on the Banach space X = (⊕n∈$\mathbb{N}$ ℓ∞n)ℓ1 contains a unique maximal ideal. We show that the same conclusion holds true for the Banach spaces X = (⊕n∈$\mathbb{N}$ ℓ∞n)ℓp and X = (⊕n∈$\mathbb{N}$ ℓ1n)ℓp whenever p ∈ (1, ∞).


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