1,720,968 research outputs found
Nonnegative solutions for a class of singular parabolic problems involving p-laplacian
No full textWe deal with the existence of nonnegative solutions u to parabolic problems with p-laplacian principal part and lower order terms which are singular in the u variabl
Corrigendum to “Homogenization of elliptic problems involving interfaces and singular data” [Nonlinear Anal. 189 (2019) 111562]
No full textSINGULAR PARABOLIC PROBLEMS WITH POSSIBLY CHANGING SIGN DATA
No full textWe show the existence of bounded solutions u epsilon L-2(0, T; H-0(1)(Omega)) for a class of parabolic equations having a lower order term b(x, t, u, del u) growing quadratically in the del u-variable and singular in the u-variable on the set {u= 0}. We refer to the model problem {u(t)-Delta u=b(x,t)vertical bar del u vertical bar(2) / vertical bar u vertical bar(k) +f(x,t) in Omega x (0,T) {u(x,t) =o on partial derivative Omega x(0,T) {u(x,0) -u(0)(x) in Omega where Omega is a bounded open subset of R-N, N >= 2, 0 < T <+infinity and 0< k < 1. The data f(x, t), uo(x) can change their sign, so that the possible solution u can vanish inside QT = Omega x(0, T) even in a set of positive measure. Therefore, we have to carefully define the meaning of solution. Also b(x, t) can have a quite general sign
Complementi di Analisi Matematica II
No full textQuesto volume è rivolto agli studenti dei corsi di Analisi Matematica II che i tre autori tengono presso la Facoltà di Ingegneria Civile ed Industriale dell’Università “La Sapienza” di Roma per diversi corsi di laurea. Esso nasce dalla necessità di esporre i contenuti della prima parte di tali corsi e precisamente le funzioni di più variabili, il calcolo differenziale in più variabili, le curve algebriche piane, il calcolo integrale in due e tre variabili, il principio degli indivisibili di Cavalieri, gli integrali curvilinei, le superfici, le aree di superfici e gli integrali superficiali. Tali argomenti sono esposti in modo essenziale e sintetico, sono presentati molti esempi che illustrano la teoria e le dimostrazioni sono omesse. I testi indicati in bibliografia possono essere utili per gli approfondimenti necessari. La seconda parte del libro raccoglie molti testi d’esame degli ultimi anni accademici (dal 2011). Sono tutti svolti tranne alcuni esercizi che contengono domande di teoria e per essi si rimanda alla prima parte di questo libro o al testo di Metodi Matematici consigliato in bibliografia
Comparison results for a nonlocal singular elliptic problem
Full text linkWe provide symmetrization results in the form of mass concentration comparisons for fractional singular elliptic equations in bounded domains, coupled with homogeneous external Dirichlet conditions. Two types of comparison results are presented, depending on the summability of the right-hand side of the equation. The maximum principle arguments employed in the core of the proofs of the main results offer a nonstandard, flexible alternative to the ones described in (Arch. Ration. Mech. Anal. 239 (2021 ) 1733–1770, Theorem 31). Some interesting consequences are L p regularity results and nonlocal energy estimates for solutions
SOS MATEMATICA Ripasso di argomenti scelti per affrontare al meglio le facoltà scientifiche
No full text
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
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