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Virtual invariants of Quot schemes of surfaces
Get PDFQuot schemes are fundamental objects in the moduli theory of algebraic geometry. Quot schemes of surfaces admit natural perfect obstruction theories if we consider 1-dimensional quotients of trivial vector bundles. We study various virtual invariants of such Quot schemes using the structure of Seiberg-Witten invariants and Hilbert schemes of points. The main result expresses the virtual Quot scheme invariants universally in terms of Seiberg-Witten invariants and certain cohomological data of a surface. When a curve class is of Seiberg-Witten length N, we prove the multiplicative structural formula for the generating series of equivariant virtual Quot scheme invariants in terms of the universal series and Seiberg-Witten invariants. Furthermore, the universal series are completely determined up to the change of variables. As an application, we prove the rationality of the homological and K-theoretic descendent series for any curve classes of Seiberg-Witten length N. Explicit formulas are available in several cases for specializations to the generating series of virtual Euler characteristics and virtual -genera. For K3 surfaces, the usual virtual Quot scheme invariants vanish. We thus define and study the reduced invariants of Quot schemes. Rather surprisingly, we show that the reduced -genera of Quot schemes and Pair spaces are equal when N=1. This implies that the reduced -genera of Quot schemes are given by the Kawai-Yoshioka formula. We study the virtual Segre and Verlinde series of Quot schemes as a variation of the non-virtual Segre and Verlinde series of Hilbert schemes of points. Analogously to the conjectural algebraicity of the Segre and Verlinde series of Hilbert schemes of points, we prove that the virtual Segre and Verlinde series of Quot schemes are algebraic for any curve classes of Seiberg-Witten length N. Furthermore, we prove the virtual Segre and Verlinde correspondence relating the universal series. This, in particular, matches the virtual Segre and Verlinde series for punctual Quot schemes up to a sign
Virtual -genera of Quot schemes on surfaces
Get PDFThis paper studies the virtual -genera of Grothendieck's Quot
schemes on surfaces, thus refining the calculations of the virtual Euler
characteristics by Oprea-Pandharipande. We first prove a structural result
expressing the equivariant virtual -genera of Quot schemes
universally in terms of the Seiberg-Witten invariants. The formula is simpler
for curve classes of Seiberg-Witten length , which are defined in the paper.
By way of application, we give complete answers in the following cases: (i)
arbitrary surfaces for the zero curve class, (ii) relatively minimal elliptic
surfaces for rational multiples of the fiber class, (iii) minimal surfaces of
general type with for any curve classes. Furthermore, a blow up formula
is obtained for curve classes of Seiberg-Witten length . As a result of
these calculations, we prove that the generating series of the virtual
-genera are given by rational functions for all surfaces with
, addressing a conjecture of Oprea-Pandharipande. In addition, we study
the reduced -genera for surfaces and primitive curve classes
with connections to the Kawai-Yoshioka formula.Comment: 48 pages. Reformulation of Theorem 1 for readability. Extra
explanation for the mixed terms in section 2.2.3. Reference update
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe 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
Get PDF“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
Get PDFWe 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
Get PDFWe 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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