1,720,959 research outputs found
Reflexive rings and subrings of a product of Dedekind domains
No full textAbstractAn extension of Warfield duality for modules over rings whose integral closure is a finite product of Dedekind domains is given. Our main example illustrating the concepts also substantiates a conjecture of Matlis
Duality and self-reflexive torsion-free abelian groups
No full textAbstractWe characterize the torsion-free abelian groups G of finite rank such that Hom(−, G) defines a rank preserving duality on the category of End(G)-submodules of finite sums of copies of G. Our results provide a maximal extension of Warfield's duality result for torsion-free groups of finite rank. In order to obtain our extension, we study the torsion-free abelian groups G for which G ≅nat Hom(Hom(G, G), G)
Extension of Ideal-Theoretic Properties of a Domain to Submodules of Its Quotient Field
No full textAbstractWe examine when multiplicative properties of ideals extend to submodules of the quotient field of an integral domain. An integral domain R is stable if each non-zero ideal of R is invertible as an ideal over its ring of endomorphisms. We show that an integral domain R is stable if and only if an analogue of this invertibility property extends to submodules of the quotient field of R. By contrast, the class of integral domains for which every non-zero ideal is locally free over its ring of endomorphisms is shown to properly contain the class of domains R for which each submodule of the quotient field is locally free over its ring of endomorphisms, and we give complete characterizations of both classes of domains
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
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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