1,720,960 research outputs found
Discrete Group Actions and Spectral Geometry of Crossed Products
Full text linkThe (twisted) crossed product construction is fundamental in the theory of -algebras and in noncommutative topology since it represents the operation of forming a quotient when this is a singular, badly-behaved space. For instance, the study of noncommutative coverings, in the special case of finite abelian structure groups, shows that twisted crossed products are the noncommutative analogue of topological regular coverings. Since spectral triples are a central notion in noncommutative geometry, this makes the task of constructing spectral triples on crossed products a natural subject of interest.
In this thesis, we construct and study spectral triples on reduced twisted crossed products , where is a unital -algebra, a discrete group and a twisted action in the sense of Busby and Smith cite{busby1970representations}. For this construction we follow, as in cite{hawkins2013spectral}, the guiding principle of the Kasparov external product, combining the given Dirac operator on with a matrix valued length-type function on the group. In particular, we provide sufficient conditions so that this triple on satisfies some of the {em axioms} of noncommutative manifolds cite{connes1996gravity}: summability, regularity, compatibility with real structures, first and second order conditions and orientation cycles.
Our guide example is the spectral triple on the noncommutative -torus cite{rieffel1981c,gracia2013elements}, regarded as the crossed product . We show that our constructions generalize the usual ones on its triple
Real Spectral Triples on Crossed Products
Full text linkGiven a spectral triple on a unital -algebra and an equicontinuous
action of a discrete group on , a spectral triple on the reduced crossed
product -algebra was constructed by Hawkins, Skalski,
White and Zacharias in [On spectral triples on crossed products arising from
equicontinuous actions, Math. Scand. 113(2) (2013) 262-291], extending the
construction by Belissard, Marcolli and Reihani in [Dynamical systems on
spectral metric spaces, preprint (2010), arXiv:1008.4617], by using the
Kasparov product to make an ansatz for the Dirac operator. Supposing that the
triple on is equivariant for an action of , we show that the triple on
is equivariant for the dual coaction of . If moreover an
equivariant real structure is given for the triple on , we give
constructions for two inequivalent real structures on the triple .
We compute the KO-dimension with respect to each real structure in terms of the
KO-dimension of and show that the first and the second order conditions are
preserved. Lastly, we characterise an equivariant orientation cycle on the
triple on coming from an equivariant orientation cycle on the
triple on . We show, along the paper, that our constructions generalize the
respective constructions of the equivariant spectral triple on the
noncommutative -torus
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
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
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
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