1,720,969 research outputs found
On spanning tree congestion
Get PDFAbstractWe prove that every connected graph G of order n has a spanning tree T such that for every edge e of T the edge cut defined in G by the vertex sets of the two components of T−e contains at most n32 edges. This result solves a problem posed by Ostrovskii (M.I. Ostrovskii, Minimal congestion trees, Discrete Math. 285 (2004) 219–226)
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
A short proof of the result on actions that characterize l∞n
No full textAbstractIt is well known that, if the identity operator on an n-dimensional Banach space V can be extended to any Banach space with the same norm, then V is isometric to l∞n. We give a short proof of the result due to B. Chalmers and B. Shekhtman (Linear Algebra and its Applications 270 (1998) 155–169) saying that the identity is (in some sense) the only such operator
Minimum congestion spanning trees in planar graphs
No full textAbstractThe main purpose of the paper is to develop an approach to the evaluation or the estimation of the spanning tree congestion of planar graphs. This approach is used to evaluate the spanning tree congestion of triangular grids
Total subspaces with long chains of nowhere norming weak*-sequential closures
No full textIf a separable Banach space X is such that for some nonquasireflexive Banach space Y there exists a surjective stricty singular operator then for every countable ordinal the dual of X contains a subspace whose weak* sequential closures of orders less than are nowhere norming and whose weak* sequential closure of order coincides with
Minimal-volume projections of cubes and totally unimodular matrices
No full textAbstractAmong all linear projections onto a given linear subspace L in Rn we select those that minimize the volume of the image of the cube {x:|xi|⩽1}. The paper is devoted to a description of the shape of such images of the cube. The shape is characterized in terms of zonotopes spanned by scalar multiples of rows of totally unimodular matrices
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