CHARACTERIZATION OF SOME DISTINGUISHED CLASSES OF OPERATORS IN TERMS OF OPERATOR INEQUALITIES

In this note, we shall give some characterizations of some distin- guished classes of operators (selfadjoint, normal, unitary, unitary re ection, partial isometry and isometry) in terms of operator inequalities

Moore-Penrose inverse and operator inequalities

In this note, we shall give complete characterizations of the class of all normal operators with closed range, and the class of all selfadjoint operators with closed range multiplied by scalars in terms of some operator inequalities.peerReviewe

Moore-Penrose inverse and operator inequalities

In this note, we shall give complete characterizations of the class of all normal operators with closed range, and the class of all selfadjoint operators with closed range multiplied by scalars in terms of some operator inequalities.peerReviewe

Corrigendum to “Moore-Penrose inverse and operator inequalities” Extracta Mathematicae 30 (2015), 29 - 39

We correct a mistake which affect our main results, namely the proof of Lema 1. The main results of the article remain unchanged.peerReviewe

Operator inequalities related to the Corach--Porta--Recht inequality

We prove some refinements of an inequality due to X. Zhan in an arbitrary complex Hilbert space by using some results on the Heinz inequality. We present several related inequalities as well as new variants of the Corach--Porta--Recht inequality. We also characterize the class of operators satisfying $\left\Vert SXS^{-1}+S^{-1}XS+kX\right\Vert \geq (k+2)\left\Vert X\right\Vert$ under certain conditions.Comment: 12 Pages, to appear in Linear Algebra Appl. (LAA

Chi-square tests for generalized exponential distributions with censored data

Generalized exponential models have numerous applications particularly in reliability studies. Using the approach proposed by Bagdonavicius and Nikulin for censored data, we propose the construction of modified chi-square goodness-of-fit tests for the generalized exponentiated exponential model (GEE) and an accelerated failure time model with the generalized exponentiated exponential distribution as the baseline (AFT-GEE). Based on maximum likelihood estimators on initial data, these statistics recover the information lost while grouping data and follow chi-square distributions. The elements of the criteria tests are given explicitly. Numerical examples from simulated samples and real data have been presented to illustrate the feasibility of the proposed tests

Intersection de l'adherence de l'image d'une derivation #delta#_A avec le commutant de A"* dans des cas particuliers

SIGLECNRS T Bordereau / INIST-CNRS - Institut de l'Information Scientifique et TechniqueFRFranc