1,721,024 research outputs found
The Essential Norm of Operators on Ap α(Bn)
Get PDFIn this paper we characterize the compact operators on the weighted Bergman spaces Ap α(Bn) when 1 −1. The main result shows that an operator on Ap α(Bn) is compact if and only if it belongs to the Toeplitz algebra and its Berezin transform vanishes on the boundary of the ballFil: Mitkovski, Mishko. Clemson University; Estados UnidosFil: Suarez, Fernando Daniel. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Matemática; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Saavedra 15. Instituto Argentino de Matemática; ArgentinaFil: Wick, Brett D.. Georgia Institute Of Techology; Estados Unido
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
Random interpolating sequences in Dirichlet spaces
Get PDFIn this new version, Theorems 1.1 and 1.9 are valid under weaker assumptions and have simplified proofs. The new Theorem 1.7 gives an optimal condition for simple random interpolation in the classical Dirichlet space.We discuss random interpolating sequences in weighted Dirichlet spaces , . Ourresults in particular imply that almost sure interpolating sequences for are exactly the almost sureseparated sequences when (which covers the Hardy space ), and they are exactlythe almost sure zero sequences for when . We show that this last result remainsvalid in the classical Dirichlet space when one considers a weaker notion of interpolation, so-called simple interpolation. As a by-product we improve a sufficient condition by Rudowicz for random Carlesonmeasures in Hardy spaces
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
The duality of H^1(R^n) and BMO(R^n) with applications
No full textThe reason of interest of this thesis project goes back to the theory of Homogeneous Singular Integral operators (SIOs) on R^n.
These operators, whose a prototypical example is the Hilbert transform on R, are bounded operators on L^p(R^n) for 1<p<\infty.
As L^1 boundedness fails to hold, a natural question is whether there is a proper subspace of L^1 where these operators are bounded on L^1: this is where real Hardy spaces came in.
In Chapter 2, Real Hardy spaces H^p(R^n) are dealt with: for 01, while H^1 is a proper subspace of L^1. In the case 0<p <=1, we prove an Atomic Decomposition, meaning that we can find some special distributions, called atoms, that serve as building blocks for H^p. Lastly, we show, as suggested before, that Homogeneous SIOs are bounded from H^1 to L^1 and, conversely, that H^1 can be equivalently defined in terms of the boundedness of the Riesz transforms, the n-dimensional analogues of the Hilbert transform.
In Chapter 3, we prove that the dual space of H^1 is the space of functions of bounded mean oscillation BMO and study the main properties of the latter.
In Chapter 4, we give two applications of such duality: the first is a characterization of BMO(R^n), meaning that a locally integrable function belongs to BMO(R^n) if and only if the commutator of the pointwise product by b and any Riesz transform is a linear bounded operator on L^p(\R^n), for 1<p<\infty. This result, originally proved by R. Coifman, R. Rochberg and G. Weiss, here is obtained using a strategy highlighted by B.Wick. Finally, by a duality argument, we prove the Div-Curl lemma, which states that the dot product of two square integrable vector fields, that a priori is in L^1, in fact belongs to H^1, as soon as one vector field is divergence-free and the other is curl-free
Dispelling the Myths Behind First-author Citation Counts
Get PDFWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
Corrigenda : "stabilization in H∞R(D)"
No full textIn this corrigenda we outline the necessary changes to the paper [3] so that the main result in that paper is made correct. The mistake the author made in the previous version was that the condition that f1 being positive on the zeros of f2 was not strong enough ∞ to guarantee the existence of the logarithm in HR (D)
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