1,720,959 research outputs found
Automorphism Groups of Finite Extensions of Fields and the Minimal Ramification Problem
Full text linkWe study the following question: given a global field and finite group , what is the minimal such that there exists a finite extension with that is ramified over exactly places of ? We conjecture that the answer is for any global field and finite group . In the case when is a number field we show that the answer is always . We show that assuming Schinzel\u27s Hypothesis H the answer is always if is a number field. We show unconditionally that the answer is always if is a global function field.
We also show that for a broader class of fields than previously known, every finite group can be realized as the automorphism group of a finite extension (without restriction on the ramification).
An important new tool used in this work is a recent result of the author and C. Tsang, which says that for any finite group there exists a natural number and a subgroup of the symmetric group such that .v2: added conditional results proving Conj 1.1 and r_F(S_n)<=1 assuming Schinzel\u27s Hypothesis
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
Lower Bounds on the Least Common Multiple of a Polynomial Sequence and its Radical
Full text linkCilleruelo conjectured that for an irreducible polynomial of degree , denoting
one has He proved it in the case but it remains open
for every polynomial with .
While the tight upper bound is known, the
best known general lower bound due to Sah is
We give an improved lower bound for a special class of irreducible
polynomials, which includes the decomposable irreducible polynomials , for which we
show
We also improve Sah's lower bound for
the radical for all with and give
a further improvement
for polynomials with a small Galois group and satisfying an additional
technical condition, as well as for decomposable polynomials.Comment: v2: added second part to Theorem 2 and Corollary 1.5; added relevant
citations; v3: refined second part of Corollary 1.5 from v2 and separated it
into its own theore
Maximal Ideals in Commutative Rings and the Axiom of Choice
Full text linkIt is well-known that within Zermelo-Fraenkel set theory (ZF), the Axiom of
Choice (AC) implies the Maximal Ideal Theorem (MIT), namely that every
nontrivial commutative ring has a maximal ideal. The converse implication MIT
AC was first proved by Hodges, with subsequent proofs given by
Banaschewski and Ern\'e.
Here we give another derivation of MIT AC, aiming to make the
exposition self-contained and accessible to non-experts with only introductory
familiarity with commutative ring theory and naive set theory.Comment: v2: fixed a couple of small error
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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