1,720,966 research outputs found
The N = 1 Triplet Vertex Operator Superalgebras: Twisted Sector
No full textWe classify irreducible σ-twisted modules for the N = 1 super triplet vertex operator superalgebra SW(m) introduced recently [Adamovic D., Milas A., Comm. Math. Phys., to appear, arXiv:0712.0379]. Irreducible graded dimensions of σ-twisted modules are also determined. These results, combined with our previous work in the untwisted case, show that the SL(2,Z)-closure of the space spanned by irreducible characters, irreducible supercharacters and σ-twisted irreducible characters is (9m + 3)-dimensional. We present strong evidence that this is also the (full) space of generalized characters for SW(m). We are also able to relate irreducible SW(m) characters to characters for the triplet vertex algebra W(2m + 1), studied in [Adamovic D., Milas A., Adv. Math. 217 (2008), 2664-2699, arXiv:0707.1857].This paper is a contribution to the Special Issue on Kac–Moody Algebras and Applications. The second author was partially supported by NSF grant DMS-0802962
The N = 1 Triplet Vertex Operator Superalgebras: Twisted Sector
Full text linkWe classify irreducible σ-twisted modules for the N = 1 super triplet vertex operator superalgebra SW(m) introduced recently [Adamovic D., Milas A., Comm. Math. Phys., to appear, arXiv:0712.0379]. Irreducible graded dimensions of σ-twisted modules are also determined. These results, combined with our previous work in the untwisted case, show that the SL(2,Z)-closure of the space spanned by irreducible characters, irreducible supercharacters and σ-twisted irreducible characters is (9m + 3)-dimensional. We present strong evidence that this is also the (full) space of generalized characters for SW(m). We are also able to relate irreducible SW(m) characters to characters for the triplet vertex algebra W(2m + 1), studied in [Adamovic D., Milas A., Adv. Math. 217 (2008), 2664-2699, arXiv:0707.1857].This paper is a contribution to the Special Issue on Kac–Moody Algebras and Applications. The second author was partially supported by NSF grant DMS-0802962
Conformal embeddings in affine vertex superalgebras
Full text linkThis paper is a natural continuation of our previous work on conformal embeddings of vertex algebras [6], [7], [8]. Here we consider conformal embeddings in simple affine vertex superalgebra Vk(g) where g=g0 ̄⊕g1 ̄ is a basic classical simple Lie superalgebra. Let Vk(g0 ̄) be the subalgebra of Vk(g) generated by g0 ̄. We first classify all levels k for which the embedding Vk(g0 ̄) in Vk(g) is conformal. Next we prove that, for a large family of such conformal levels, Vk(g) is a completely reducible Vk(g0 ̄)–module and obtain decomposition rules. Proofs are based on fusion rules arguments and on the representation theory of certain affine vertex algebras. The most interesting case is the decomposition of V−2(osp(2n+8|2n)) as a finite, non simple current extension of V−2(Dn+4)⊗V1(Cn). This decomposition uses our previous work [10] on the representation theory of V−2(Dn+4). We also study conformal embeddings gl(n|m)↪sl(n+1|m) and in most cases we obtain decomposition rules
On the semisimplicity of the category for affine Lie superalgebras
Full text linkWe study the semisimplicity of the category KLk for affine Lie superalgebras and provide a super analog of certain results from [8]. Let KLk^fin be the subcategory of KLk consisting of ordinary modules on which a Cartan subalgebra acts semisimply. We prove that KLk^fin is semisimple when 1) k is a collapsing level, 2) Wk(g,θ) is rational, 3) Wk(g,θ) is semisimple in a certain category. The analysis of the semisimplicity of KLk is subtler than in the Lie algebra case, since in super case KLk can contain indecomposable modules. We are able to prove that in many cases when KLk^fin is semisimple we indeed have KLk^fin=KLk, which therefore excludes indecomposable and logarithmic modules in KLk. In these cases we are able to prove that there is a conformal embedding W↪Vk(g) with W semisimple (see Section 10). In particular, we prove the semisimplicity of KLk for g=sl(2|1) and [Formula presented], m∈Z≥0. For g=sl(m|1), we prove that KLk is semisimple for k=−1, but for k a positive integer we show that it is not semisimple by constructing indecomposable highest weight modules in KLk^fin
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
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