1,720,976 research outputs found
Minimization of the k-th eigenvalue of the Robin-Laplacian with perimeter constraint
No full textIn this paper we address the problem of the minimization of the k-th Robin eigenvalue with positive parameter among bounded open Lipschitz sets with prescribed perimeter.
The perimeter constraint allows us to naturally generalize the problem to a setting involving more general admissible geometries made up of sets of finite perimeter with inner cracks, along with a suitable generalization of the Robin-Laplacian operator with properties which look very similar to those of the classical setting. Within this extended framework we establish existence of minimizers, and prove that the associated eigenvalue coincides with the infimum of those achieved by regular domains
A quantitative dimension free isoperimetric inequality for the fractional Gaussian perimeter
Full text linkWe prove a quantitative isoperimetric inequality for the fractional Gaussian perimeter using extension techniques. Though the exponent of the Fraenkel asymmetry is not sharp, the constant appearing in the inequality does not depend on the dimension but only on the Gaussian volume of the set and on the fractional order
Introduzione alla Analisi Complessa
Full text linkQuesti appunti sono una versione ampliata delle lezioni tenute da Michele
Carriero nel Corso di Analisi Complessa per gli Studenti della Laurea
Magistrale in Matematica dell'Università del Salento.
Il secondo autore è uno dei partecipanti al Corso nell'a.a. 2011-2012; a
lui va riconosciuto l'impegno per la cura di questa versione, a partire dagli
appunti delle lezioni tenute in diversi anni
Local regularity of very weak -harmonic functions via fractional difference quotients
Full text linkThe aim of this paper is to give a new proof that any very weak s-harmonic function u in the unit ball B is smooth. As a first step, we improve the local summability properties of u. Then, we exploit a suitable version of the difference quotient method tailored to get rid of the singularity of the integral kernel and gain Sobolev regularity and local linear estimates of the Hlocs norm of u. Finally, by applying more standard methods, such as elliptic regularity and Schauder estimates, we reach the real analyticity of u. Up to the authors’ knowledge, the difference quotient techniques are new
Stability of the Gaussian Faber–Krahn inequality
Full text linkWe prove a quantitative version of the Gaussian Faber–Krahn type inequality proved in
(Betta et al. in Z. Angew. Math. Phys. 58:37–52, 2007) for the first Dirichlet eigenvalue of
the Ornstein–Uhlenbeck operator, estimating the deficit in terms of the Gaussian Fraenkel
asymmetry. As expected, the multiplicative constant only depends on the prescribed Gaussian
measure
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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