1,720,958 research outputs found
Geometric invariants and Geometric consistency of Manin’s conjecture
No full textManin’s conjeture states that the asymptotic growth of the number of rational points
on a Fano variety over a number field is governed by certain geometric invariants (a
and b-constants). In this thesis we study the behaviour of these geometric invariants
and show that Manin’s conjecture is geometrically consistent. In the first part, we
study the behaviour of the b-constant in families and show that the b-constant is
constant on very general fibers of a family of algebraic varieties. If the fibers of the
family are uniruled, then we show that the b-constant is constant on general fibers.
In the second part, we study the behaviour of the a-constant (Fujita invariant) under
pull-back to generically finite covers and prove a conjecture of Lehmann-Tanimoto
about finiteness of covers. In the last part, based on joint work with B. Lehmann
and S. Tanimoto, we prove geometric consistency of Manin’s conjecture by showing
that the rational points contributed by subvarieties or covers with larger geometric
invariants are contained in a thin set
Geometric invariants and Geometric consistency of Manin’s conjecture
No full textManin’s conjeture states that the asymptotic growth of the number of rational points
on a Fano variety over a number field is governed by certain geometric invariants (a
and b-constants). In this thesis we study the behaviour of these geometric invariants
and show that Manin’s conjecture is geometrically consistent. In the first part, we
study the behaviour of the b-constant in families and show that the b-constant is
constant on very general fibers of a family of algebraic varieties. If the fibers of the
family are uniruled, then we show that the b-constant is constant on general fibers.
In the second part, we study the behaviour of the a-constant (Fujita invariant) under
pull-back to generically finite covers and prove a conjecture of Lehmann-Tanimoto
about finiteness of covers. In the last part, based on joint work with B. Lehmann
and S. Tanimoto, we prove geometric consistency of Manin’s conjecture by showing
that the rational points contributed by subvarieties or covers with larger geometric
invariants are contained in a thin set
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
Strong Algebras and Radical Sylvester-Gallai Configurations
Full text linkIn this paper, we prove the following non-linear generalization of the
classical Sylvester-Gallai theorem. Let be an algebraically closed
field of characteristic , and be a set of irreducible homogeneous polynomials of
degree at most such that is not a scalar multiple of for . Suppose that for any two distinct , there is such that . We prove that such radical SG
configurations must be low dimensional. More precisely, we show that there
exists a function , independent of
and , such that any such configuration must
satisfy
Our result confirms a conjecture of Gupta [Gup14, Conjecture 2] and
generalizes the quadratic and cubic Sylvester-Gallai theorems of [S20,OS22].
Our result takes us one step closer towards the first deterministic polynomial
time algorithm for the Polynomial Identity Testing (PIT) problem for depth-4
circuits of bounded top and bottom fanins. Our result, when combined with the
Stillman uniformity type results of [AH20a,DLL19,ESS21], yields uniform bounds
for several algebraic invariants such as projective dimension, Betti numbers
and Castelnuovo-Mumford regularity of ideals generated by radical SG
configurations.Comment: 62 pages. Comments are welcome
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
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