Results 11 to 20 of about 218 (47)
On Motzkin sequence spaces via q-analog and compact operators
Demonstratio MathematicaWe aim to develop a qq-analog of recently introduced Motzkin sequence spaces by Erdem et al. [Motzkin sequence spaces and Motzkin core, Numer. Funct. Anal. Optim. 45 (2024), no.
Yaying Taja, Mursaleen Mohammad
doaj +1 more source
Approximation numbers of composition operators on the Hardy space of the ball and of the polydisk [PDF]
, 2015 We give general estimates for the approximation numbers of composition operators on the Hardy space on the ball $B\_d$ and the polydisk $D^d$
Li, Daniel +2 more
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Operator Ky Fan type inequalities
, 2018 In this paper, we extend some significant Ky Fan type inequalities in a large setting to operators on Hilbert spaces and derive their equality conditions.
Habibzadeh, S. +2 more
core +1 more source
Regular perturbation of V -geometrically ergodic Markov chains
, 2012 In this paper, new conditions for the stability of V-geometrically ergodic Markov chains are introduced. The results are based on an extension of the standard perturbation theory formulated by Keller and Liverani.
Ferré, Déborah +2 more
core +3 more sources
Hyperinvariant subspace for absolutely norm attaining and absolutely minimum attaining operators
, 2020 A bounded linear operator $T$ defined on a Hilbert space $H$ is called \textit{norm attaining} if there exist $x\in H$ with unit norm such that $\|Tx\|=\|T\|$.
Bala, Neeru, Ramesh, Golla
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On the gradient estimates for evolution operators associated to Kolmogorov operators [PDF]
, 2013 We determine sufficient conditions for the occurrence of a pointwise gradient estimate for the evolution operators associated to nonautonomous second order parabolic operators with (possibly) unbounded coefficients.
Angiuli, Luciana
core
On $(p,r)$-null sequences and their relatives [PDF]
, 2014 Let $1\leq p < \infty$ and $1\leq r \leq p^\ast$, where $p^\ast$ is the conjugate index of $p$. We prove an omnibus theorem, which provides numerous equivalences for a sequence $(x_n)$ in a Banach space $X$ to be a $(p,r)$-null sequence.
Ain, Kati, Oja, Eve
core
Disjointly homogeneous Banach lattices and applications
, 2015 This is a survey on disjointly homogeneous Banach lattices and their applicactions. Several structural properties of this class are analyzed. In addition we show how these spaces provide a natural framework for studying the compactness of powers of ...
Flores, Julio +2 more
core +1 more source
A note on compact operators and operator matrices [PDF]
, 1999 In this note two properties of compact operators acting on a separable Hilbert space are discussed. In the first part a characterization of compact operators is obtained for bounded operators represented as tri-block diagonal matrices with finite blocks.
B. Guljaš, D. Bakić
core
Weak compactness and essential norms of integration operators [PDF]
, 2011 Let $g$ be an analytic function on the unit disc and consider the integration operator of the form $T_g f(z) = \int_0^z fg'\,d\zeta$. We show that on the spaces $H^1$ and $BMOA$ the operator $T_g$ is weakly compact if and only if it is compact.
Laitila, Jussi +2 more
core