1,720,960 research outputs found
Tropicalization of the universal Jacobian
Full text linkIn this article we provide a stack-theoretic framework to study the universaltropical Jacobian over the moduli space of tropical curves. We develop twoapproaches to the process of tropicalization of the universal compactifiedJacobian over the moduli space of curves -- one from a logarithmic and theother from a non-Archimedean analytic point of view. The central result fromboth points of view is that the tropicalization of the universal compactifiedJacobian is the universal tropical Jacobian and that the tropicalization mapsin each of the two contexts are compatible with the tautological morphisms. Ina sequel we will use the techniques developed here to provide explicitpolyhedral models for the logarithmic Picard variety.Comment: 51 pages, 2 figures, v3: published versio
The logarithmic Picard group and its tropicalization
No full textISSN:0010-437XISSN:1570-5846ISSN:1570-584
Relative Moduli of Vector Bundles and the Log-Minimal Model Program on Mg
Full text linkRecent work on the log-minimal model program for the moduli space of curves, as well as past results of Caporaso, Pandharipande, and Simpson motivate an investigation of compactifications of the universal moduli space of slope semi-stable vector bundles over moduli spaces of curves arising in the Hassett{Keel program. Our main result is the construction of a compactification of the universal moduli space of vector bundles over several of these moduli spaces, along with a complete description in the case of pseudo-stable curves
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
Geometric Realization of Strata in the Boundary of the Intermediate Jacobian Locus
Full text linkIn this thesis we describe intermediate Jacobians of threefolds obtained from singular cubic threefolds. By this we mean two things. First, we describe the intermediate Jacobian of a desingularization of a cubic threefold with isolated singularities. Second, we describe limits of intermediate Jacobians of smooth cubic threefolds, as the family of cubic threefolds acquires isolated singularities. In regards to the first question, generalizing a result of Clemens--Griffiths we show specifically that the intermediate Jacobian of a distinguished desingularization of a cubic threefold with a single singularity of type is the Jacobian of the normalization of an associated complete intersection curve in , the so called -curve. In regards to degenerations, we describe how the limit intermediate Jacobian, under certain conditions, can be described as a semi-abelian variety as the extension of a torus by the finite quotient of the product of Jacobians of curves, where one of the curves is the normalization of the -curve associated to the cubic threefold and a choice of singularity, and the other curves are so-called tails arising from stable reduction of plane curve singularities
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
Geometric Realization of Strata in the Boundary of the Intermediate Jacobian Locus
Full text linkIn this thesis we describe intermediate Jacobians of threefolds obtained from singular cubic threefolds. By this we mean two things. First, we describe the intermediate Jacobian of a desingularization of a cubic threefold with isolated singularities. Second, we describe limits of intermediate Jacobians of smooth cubic threefolds, as the family of cubic threefolds acquires isolated singularities. In regards to the first question, generalizing a result of Clemens--Griffiths we show specifically that the intermediate Jacobian of a distinguished desingularization of a cubic threefold with a single singularity of type is the Jacobian of the normalization of an associated complete intersection curve in , the so called -curve. In regards to degenerations, we describe how the limit intermediate Jacobian, under certain conditions, can be described as a semi-abelian variety as the extension of a torus by the finite quotient of the product of Jacobians of curves, where one of the curves is the normalization of the -curve associated to the cubic threefold and a choice of singularity, and the other curves are so-called tails arising from stable reduction of plane curve singularities
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
Relative Moduli of Vector Bundles and the Log-Minimal Model Program on Mg
Full text linkRecent work on the log-minimal model program for the moduli space of curves, as well as past results of Caporaso, Pandharipande, and Simpson motivate an investigation of compactifications of the universal moduli space of slope semi-stable vector bundles over moduli spaces of curves arising in the Hassett{Keel program. Our main result is the construction of a compactification of the universal moduli space of vector bundles over several of these moduli spaces, along with a complete description in the case of pseudo-stable curves
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