1,721,723 research outputs found
Connecting M-theory and type IIB parameterizations in exceptional field theory
No full textIn exceptional field theory, there are two natural parameterizations for the generalized metric: in terms of bosonic fields in eleven-dimensional supergravity (M-theory parameterization), and type IIB supergravity (type IIB parameterization). In order to translate various results known in M-theory to type IIB theory or vice versa, an explicit map between the two parameterizations would be useful. In this note, we present such a linear map. Comparing the two parameterizations under the linear map, we reproduce the known T-duality transformation rules for the supergravity fields. We also obtain the T-duality rules for non-geometric beta-/gamma-fields appearing in the type II theory on a torus. © The Author(s) 2017. Published by Oxford University Press on behalf of the Physical Society of Japan.2311Nsciescopu
η-symbols in exceptional field theory
No full textWe present the universal form of eta-symbols that can be applied to an arbitrary E-d(d) exceptional field theory (EFT) up to d = 7. We then express the Y-tensor, which governs the gauge algebra of EFT, as a quadratic form of the eta-symbols. The usual definition of the Y-tensor strongly depends on the dimension of the compactification torus while it is not the case for our Y-tensor. Furthermore, using the eta-symbols, we propose a universal form of the linear section equation. In particular, in the SL(5) EFT, we explicitly show the equivalence to the known linear section equation. © The Author(s) 2017. Published by Oxford University Press on behalf of the Physical Society of Japan.11Nsciescopu
Untitled (in memory of Mr. Yoshinao Sakatani) 阪谷芳直氏を偲んで
No full textMemories of Mr. Yoshinao Sakatanihttp://deepblue.lib.umich.edu/bitstream/2027.42/108114/1/Sakatani memorial.pd
Homogeneous Yang–Baxter deformations as generalized diffeomorphisms
No full textYang-Baxter (YB) deformations of string sigma model provide deformed target spaces. We propose that homogeneous YB deformations always lead to a certain class of beta-twisted backgrounds and represent the bosonic part of the supergravity fields in terms of the classical r-matrix associated with the YB deformation. We then show that various beta-twisted backgrounds can be realized by considering generalized diffeomorphisms in the undeformed background. Our result extends the notable relation between the YB deformations and (non-commuting) TsT transformations. We also discuss more general deformations beyond the YB deformations. © 2017 IOP Publishing Ltd Printed in the UK101011Nsciescopu
Going Beyond Counting First Authors in Author Co-citation Analysis
No full textThe 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
Generalized gravity from modified DFT
No full textRecently, generalized equations of type IIB supergravity have been derived from the requirement of classical kappa-symmetry of type IIB superstring theory in the Green-Schwarz formulation. These equations are covariant under generalized T -duality transformations and hence one may expect a formulation similar to double field theory (DFT). In this paper, we consider a modification of the DFT equations of motion by relaxing a condition for the generalized covariant derivative with an extra generalized vector. In this modified double field theory (mDFT), we show that the flatness condition of the modified generalized Ricci tensor leads to the NS-NS part of the generalized equations of type IIB supergravity. In particular, the extra vector fields appearing in the generalized equations correspond to the extra generalized vector in mDFT. We also discuss duality symmetries and a modification of the string charge in mDFT
Variations on the Author
No full text“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
No full textWe 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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