1,720,957 research outputs found
Equivalences of additive categories
Full text linkIn the first part of the thesis, after an introduction of the concept of recollement
and TTF triple in a triangulated category, we consider recollements of derived categories
of differential graded algebras induced by self-orthogonal compact objects
obtaining a generalization of Rickard's Theorem. Specializing to the case of partial
tilting modules over a ring, we extend the results on triangle equivalences proved
in [B] and [BMT]. After that we focus on the connection between recollements
of derived categories of rings, bireflective subcategories and generalized universal
localizations". In the second part of the thesis we give some results in the setting
of monoidal categories and dual qausi-bialgebras. To every dual quasi-bialgebra H
and every bialgebra R in the category of Yetter-Drinfeld modules over H, one can
associate a dual quasi-bialgebra, called bosonization. In this thesis, using the fundamental
theorem, we characterize as bosonizations the dual quasi-bialgebras with
a projection onto a dual quasi-bialgebra with a preantipode. As an application we
investigate the structure of the graded coalgebra grA associated to a dual quasibialgebra
A with the dual Chevalley property (e.g. A is pointed)
Preantipodes for Dual Quasi-Bialgebras
No full textIt is known that a dual quasi-bialgebra with antipode H, i.e. a dual quasi-Hopf algebra, fulfils a fundamental theorem for right dual quasi-Hopf H-bicomodules. The converse in general is not true. We prove that, for a dual quasi-bialgebra H, the structure theorem amounts to the existence of a suitable map S : H --> H that we call a preantipode of H
Bosonization for dual quasi-bialgebras and preantipode
No full textTo every dual quasi-bialgebra H and every bialgebra R in the category of Yetter-Drinfeld modules over H, one can associate a dual quasi-bialgebra, called bosonization. In this paper, using the fundamental theorem, we characterize as bosonizations the dual quasi-bialgebras with a projection onto a dual quasi-bialgebra with a preantipode. As an application we investigate the structure of the graded coalgebra gr. A associated to a dual quasi-bialgebra A with the dual Chevalley property (e.g. A is pointed)
Recollements from partial tilting complexes
No full textWe consider recollements of derived categories of differential
graded algebras induced by self-orthogonal compact objects obtaining a generalization of Rickard’s Theorem. Specializing to the case of partial tilting modules over a ring, we extend previous results on triangle equivalences]. In the end we focus on the connection between recollements of derived categories of rings, bireflective subcategories and “generalized universal localizations”
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe 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
Full text link“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
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe 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
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe 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
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