1,720,960 research outputs found
Actions and semi-direct products in categories of groups with action
Full text linkDerived actions in the category of groups with action on itself Gr• are defined and de-scribed. This category plays a crucial role in the solution of two problems of Loday stated in the literature. A full subcategory of reduced groups with action rGr• of Gr• is intro-duced, which is not a category of interest but has some properties, which can be applied in the investigation of action representability in this category; these properties are similar to those, which were used in the construction of universal strict general actors in the category of interest. Semi-direct product constructions are given in Gr• and rGr• and it is proved that an action is a derived action in Gr• (resp. rGr•) if and only if the corresponding semi-direct product is an object of Gr• (resp. rGr•). The results obtained in this paper will be applied in the forthcoming paper on the representability of actions in the category rGr•
Kan extensions of internal functors. Nonconnected case
No full textAbstractAn investigation of internal Kan extensions started in Datuashvili (Georgian Math. J. 6 (2) (1999) 127–148) is continued. The necessary and sufficient conditions for its existence are given, which generalizes the result obtained in Datuashvili for the case when the domain internal categories in the Kan extension diagram are connected
Pentactions and action representability in the category of reduced groups with action
Full text linkA notion of pentaction of any object in the category
of reduced groups with action is introduced. The operations are defined in the
set of pentactions of an object of
. It is proved that if an object is perfect with
zero weak stabilizer in the sense defined in the paper, then
is an object of , it has a
derived action on , the object is action representable and
represents all actions on .Comment: 20 pages, research paper, LaTeX2e, xypi
Actions and semi-direct products in categories of groups with action
Full text linkDerived actions in the category of groups with action on itself
are defined and described. This category plays a
crucial role in the solution of Loday's two problems stated in the literature.
A full subcategory of reduced groups with action of
is introduced, which is not a category of interest but
has some properties, which can be applied in the investigation of action
representability in this category; these properties are similar to those, which
were used in the construction of universal strict general actors in the
category of interest. Semi-direct product constructions are given in
and and it is proved that an
action is a derived action in (resp.
) if and only if the corresponding semi-direct product
is and object of (resp. ). The
results obtained in this paper will be applied in the forthcoming paper on the
representability of actions in the category .Comment: 12 pages, research paper, LaTeX2e, xypi
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
Closed model category structures on the category of chain functors
No full textAbstractIn the category Ch of chain functors one can introduce fibrations (Section 3), cofibrations and weak equivalences (Section 4), satisfying all the properties of a closed model category as defined by D. Quillen except for the existence of finite limits and colimits. Nevertheless we show that there exists a canonically defined suspension—as well as a loop functor, which are invertible, turning the homotopy category Chh into a stable category (Section 8)
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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