1,721,154 research outputs found
On a binary operation for positive operators
No full textM. Lin defined a binary operation for two positive semi-definite matrices in studying certain determinantal inequalities that arise from diffusion tensor imaging. This operation enjoys some interesting properties similar to the operator geometric mean. We study this operationfurther and present numerous properties emphasizing the relationship with the operator geometric mean. In the end, we present an application toward Tsallis relative operator entropy.Fil: Furuichi, Shigeru. Nihon University; JapónFil: Moradi, Hamid Reza. Islamic Azad University; IránFil: Conde, Cristian Marcelo. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Area de Matematica (area de Matematica) ; Instituto de Ciencias ; Universidad Nacional de General Sarmiento;Fil: Sababheh, Mohammad. Princess Sumaya University For Technology; Jordani
Operator Bohr-Type inequalities
No full textThe classical Bohr inequality for scalars was extended to the non-commutative case of Hilbert space operators in the literature. The sole goal of this article is to discuss the operator Bohr inequality and present some of its new variants. This includes fresh reverses and re nements of this inequality with applications towards an operators real and imaginary parts, not to forget the new discussion of di erent domains of the parameters. One further application towards the operator Dunkl-Williams inequality will be presented too. While the new results are interesting, we emphasize that the approach used to explore these inequalities di ers from the existing literature methods for this context.Fil: Sababheh, Mohammad. Princess Sumaya University For Technology; JordaniaFil: Conde, Cristian Marcelo. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Area de Matematica (area de Matematica) ; Instituto de Ciencias ; Universidad Nacional de General Sarmiento;Fil: Reza Moradi, Hamid. Islamic Azad University; Irá
Generalized Euclidean operator radius
No full textIn this paper, we introduce the f -operator radius of Hilbert space operators as a generalization of theEuclidean operator radius and the q-operator radius. The properties of the newly defined radius are discussed, emphasizing how it extends some known results in the literature.Fil: Alomari, Mohammad W.. Jadara University; JordaniaFil: Sababheh, Mohammad. Princess Sumaya University For Technology; JordaniaFil: Conde, Cristian Marcelo. Area de Matematica (area de Matematica) ; Instituto de Ciencias ; Universidad Nacional de General Sarmiento; . Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Moradi, Hamid Reza. Islamic Azad University; Irá
On the matrix Cauchy-Schwarz inequality
Get PDFRevista con referatoFil: Conde, Cristian Marcelo. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina.Fil: Conde, Cristian Marcelo. Universidad Nacional de General Sarmiento. Instituto de Ciencias; Argentina.Fil: Reza Moradi, Hamid. Islamic Azad University; Irán.Abstract. The main goal of this work is to present new matrix inequalities of Cauchy-Schwarz
type. In particular, we investigate the so-called Lieb functions, whose definition came as an
umbrella of Cauchy-Schwarz-like inequalities, then we consider the mixed Cauchy-Schwarz inequality. This latter inequality has been influential in obtaining several other matrix inequalities,
including numerical radius and norm results. Among many other results, we show that
T
1
4 (|T|+|T∗|+2RT+|T|+|T∗| −2RT),
where RT is the real part of the matrix T
Norm Inequalities via Convex and Log-Convex Functions
No full textIn this paper, we study the norm and skew angular distances in a normed space X, where convex functions are used to obtain refinements and reverses of some outstanding results in the literature. For example, in this regard, we show that if a, b∈ X are non-zero and if p, q> 0 are such that 1p+1q=1, then 2λ(pr∥a∥r+qr∥b∥r2-∥pa+qb2∥r)≤pr-1∥a∥r+qr-1∥b∥r-∥a+b∥r≤2μ(pr∥a∥r+qr∥b∥r2-∥pa+qb2∥r),where r≥ 1 , λ= min { 1 / p, 1 / q} and μ= max { 1 / p, 1 / q}. Then we explain how this result extends some known results in the literature. Many other related results will be also shown. Then, with the theme of convexity, we employ a log-convex approach on certain matrix functions to obtain improvements and new sights of some matrix inequalities, including possible bounds of ‖ AtXB1-t‖ , where A, B are positive definite matrices, X is an arbitrary matrix, ‖ · ‖ is a unitarily invariant norm and 0 ≤ t≤ 1. Many other results involving matrix and scalar log-convex functions will be presented too.Fil: Conde, Cristian Marcelo. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Area de Matematica (area de Matematica) ; Instituto de Ciencias ; Universidad Nacional de General Sarmiento;Fil: Minculete, Nicusor. Transilvania University; RumaniaFil: Moradi, Hamid Reza. Payame Noor University; IránFil: Sababheh, Mohammad. Princess Sumaya University For Technology; Jordani
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Get PDF“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Generalized Euclidean operator radius
No full textRevista con referatoFil: Conde, Cristian Marcelo. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina.Fil: Conde, Cristian Marcelo. Universidad Nacional de General Sarmiento. Instituto de Ciencias; Argentina.Fil: Reza Moradi, Hamid. Islamic Azad University; Irán.En este artículo, presentamos el radio del operador f de los operadores del espacio de Hilbert como una generalización del radio del operador euclidiano y del radio del operador q. Se discuten las propiedades del radio recién definido, destacando cómo extiende algunos resultados conocidos en la literatura.In this paper, we introduce the f-operator radius of Hilbert space operators as a generalization of the Euclidean operator radius and the q-operator radius. The properties of the newly defined radius are discussed, emphasizing how it extends some known results in the literature.En este artículo, presentamos el radio del operador f de los operadores del espacio de Hilbert como una generalización del radio del operador euclidiano y del radio del operador q. Se discuten las propiedades del radio recién definido, destacando cómo extiende algunos resultados conocidos en la literatura
Appropriate Similarity Measures for Author Cocitation Analysis
Get PDFWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
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