1,722,152 research outputs found
- estimates for damped wave equations with odd initial data
No full textWe study the Cauchy problem for the damped wave equation. In a previous paper [16] the author has shown the - estimates between the solutions of the damped wave equation and the solutions of the corresponding heat equation. In this paper, we show new - estimates for the damped wave equation with odd initial data
Renormings of L-p(L-q)
No full textWe investigate the best order of smoothness of L-p(L-q). We prove in particular that there exists a C-infinity-smooth bump function on L-p(L-q) if and only if p and q are even integers and p is a multiple of q.Depto. de Análisis Matemático y Matemática AplicadaFac. de Ciencias MatemáticasTRUEpu
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
L^p - L^q ESTIMATES FOR SUBELLIPTIC PSEUDO-DIFFERENTIAL OPERATORS ON COMPACT LIE GROUPS
Get PDFWe establish the L^p-L^q-boundedness of subelliptic pseudo-differential operators on a compact Lie group G. Effectively, we deal with the L^p-L^q-bounds for operators in the sub-Riemmanian setting because the subelliptic classes are associated to a Hörmander sub-Laplacian. The Riemannian case associated with the Laplacian is also included as a special case. Then, applications to the L^p-L^q-boundedness of pseudo-differential operators in the Hörmander classes on G are given in the complete range 0 ≤ δ ≤ ρ ≤ 1, δ < 1. This also gives the L^p-L^q-bounds in the Riemannian setting, because the later classes are associated with the Laplacian on G. In both cases, in the Riemannian and the sub-Riemannian settings, necessary and sufficient conditions for the L^p-L^q-boundedness of operators are also analysed
- estimates for subelliptic pseudo-differential operators on compact Lie groups
Get PDFWe establish the --boundedness of subelliptic pseudo-differential
operators on a compact Lie group . Effectively, we deal with the
--bounds for operators in the sub-Riemmanian setting because the
subelliptic classes are associated to a H\"ormander sub-Laplacian. The
Riemannian case associated with the Laplacian is also included as a special
case. Then, applications to the --boundedness of pseudo-differential
operators in the H\"ormander classes on are given in the complete range
This also gives the
--bounds in the Riemannian setting, because the later classes are
associated with the Laplacian on . In both cases, in the Riemannian and the
sub-Riemannian settings, necessary and sufficient conditions for the
--boundedness of operators are also anaysed.Comment: 22 Page
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
L^p-L^q hypergeometric spectral and Fourier multipliers associated with root systems
No full textIn this paper, we prove Hormander's L-p-L-q multiplier theorem for the hypergeometric (or Heckman-Opdam) Fourier multipliers associated with root systems for the range 1<p <= 2 <= q<infinity. We also establish the L-p-L-q boundedness of spectral multipliers of the Heckman-Opdam Laplacian and consequently we obtain time asymptotics for the L-p-L-q norms of the hypergeometric heat kernels and the Sobolev-type embedding for the Heckman-Opdam Laplacian. The proof hinges on the Paley and Hausdorff-Young-Paley inequalities for the hypergeometric Fourier transform (also known as the Heckman-Opdam transform) associated with root systems. Moreover, we also study the aforementioned spectral multiplier results in the compact Heckman-Opdam setting.In this paper, we prove Hormander's L-p-L-q multiplier theorem for the hypergeometric (or Heckman-Opdam) Fourier multipliers associated with root systems for the range 1<p <= 2 <= q<infinity. We also establish the L-p-L-q boundedness of spectral multipliers of the Heckman-Opdam Laplacian and consequently we obtain time asymptotics for the L-p-L-q norms of the hypergeometric heat kernels and the Sobolev-type embedding for the Heckman-Opdam Laplacian. The proof hinges on the Paley and Hausdorff-Young-Paley inequalities for the hypergeometric Fourier transform (also known as the Heckman-Opdam transform) associated with root systems. Moreover, we also study the aforementioned spectral multiplier results in the compact Heckman-Opdam setting.A
L^p -L^q boundedness of Fourier multipliers on quantum Euclidean spaces
No full textIn this paper, we study Fourier multipliers on quantum Euclidean spaces and obtain results on their L^p − L^q boundedness. On the way to get these results, we prove Paley, Hausdorff-Young-Paley, and Hardy-Littlewood inequalities on the quantum Euclidean space. As applications, we establish the L^p−L^q estimate for the heat semigroup and Sobolev embedding theorem on quantum Euclidean spaces. We also obtain quantum analogues of logarithmic Sobolev and Nash type inequalities.In this paper, we study Fourier multipliers on quantum Euclidean spaces and obtain results on their L^p − L^q boundedness. On the way to get these results, we prove Paley, Hausdorff-Young-Paley, and Hardy-Littlewood inequalities on the quantum Euclidean space. As applications, we establish the L^p−L^q estimate for the heat semigroup and Sobolev embedding theorem on quantum Euclidean spaces. We also obtain quantum analogues of logarithmic Sobolev and Nash type inequalities.
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
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