We consider the existence, multiplicity of positive solutions for the integral boundary value problem with φ-Laplacian φ u′ t ′ f t, u t , u′ t 0, t ∈ 0, 1 , u 0 ∫1 0 u r g r dr, u 1 ∫1 0 u r h r dr, where φ is an odd, increasing homeomorphism from R onto R. We show that it has at least one, two, or three positive solutions under some assumptions by applying fixed point theorems. The interestin...

Let f(t) be a real continuous function on an interval, and consider the operator function f(X) defined for Hermitian operators X. We will show that if f(X) is increasing w.r.t. the operator order, then for F (t) = ∫ f(t)dt the operator function F (X) is convex. Let h(t) and g(t) be C1 functions defined on an interval I. Suppose h(t) is non-decreasing and g(t) is increasing. Then we will define ...

Let E be a Banach lattice, T be a bounded operator on E. The Weyl essential spectrum σew(T ) of the operator T is a set σew(T ) = ∩ K∈K(E) σ(T + K), where K(E) is a set of all compact operators on E. In particular for a positive operator T next subsets of the spectrum

Let T be a positive operator on a Banach lattice E. Some properties of Weyl essential spectrum σew(T ), in particular, the equality σew(T ) = ⋂ 0≤K∈K(E) σ(T +K), where K(E) is the set of all compact operators on E, are established. If r(T ) does not belong to Fredholm essential spectrum σef(T ), then r(T ) 6∈ σ(T +a|T−1|) for every a 6= 0, where T−1 is a residue of the resolvent R(., T ) at r(T...

We examine k-minimal and k-maximal operator spaces and operator systems, and investigate their relationships with the basic separability problem in quantum information theory. We show that the matrix norms that define the k-minimal operator spaces are equal to a family of norms that have been studied independently as a tool for detecting k-positive linear maps and bound entanglement. Similarly,...

let $varphi(z)=z^m, z in mathbb{u}$, for some positive integer $m$, and $c_varphi$ be the composition operator on the bergman space $mathcal{a}^2$ induced by $varphi$. in this article, we completely determine the point spectrum, spectrum, essential spectrum, and essential norm of the operators $c^*_varphi c_varphi, c_varphi c^*_varphi$ as well as self-commutator and anti-self-commutators of $c_...

Parallel subtraction is an operation defined on pairs of positive operators. In terms of electrical networks, one may pose the following problem: Given an electrical network, represented by a specified positive operator, determine the set of positive operators which when connected in parallel with the specified operator yield another prescribed operator. The set of solutions of this electrical ...

Sign type spectra are an important tool in the investigation of spectral properties of selfadjoint operators in Krein spaces. It is our aim to show that also sign type spectra for normal operators in Krein spaces provide insight in the spectral nature of the operator: If the real part and the imaginary part of a normal operator in a Krein space have real spectra only and if the growth of the re...

‎In this short note‎, ‎we present some inequalities for relative operator entropy which are generalizations of some results obtained by Zou [Operator inequalities associated with Tsallis relative operator entropy‎, ‎{em Math‎. ‎Inequal‎. ‎Appl.}‎ ‎{18} (2015)‎, ‎no‎. ‎2‎, ‎401--406]‎. ‎Meanwhile‎, ‎we also show some new lower and upper bounds for relative operator entropy and Tsallis relative o...