1,966 research outputs found
A strong comparison principle for the p-laplacian
No full textWe consider weak solutions of the differential inequality of p-Laplacian type -(p)u - f(u) <= - Delta(p)v - f(v) such that u <= v on a smooth bounded domain in RN and either u or v is a weak solution of the corresponding Dirichlet problem with zero boundary condition. Assuming that u < v on the boundary of the domain we prove that u < v, and assuming that u equivalent to v equivalent to 0 on the boundary of the domain we prove u < v unless u equivalent to v. The novelty is that the nonlinearity f is allowed to change sign. In particular, the result holds for the model nonlinearity f(s) = s(q) - lambda s(p-1) with q > p - 1
Dimostrare è calcolare
No full text"Questo articolo propone un formalismo per la presentazione di dimostrazioni sia su supporto cartaceo, che su supporto elettronico.
Il lavoro trae ispirazione dall'isomorfismo di Curry-Howard tra dimostrazioni costruttive e programmi funzionali.
Algorithms, unaffected by the Schwarz paradox, approximating tangent planes and area of smooth surfaces via inscribed triangular polyhedra
No full textIn this work we provide an algorithm approximating the tangent bivector at a point of a smooth surface through inscribed triangles converging to the point, regardless their form or position with respect to the tangent plane. This result is obtained approximating Jacobian determinants of smooth plane transformations at a point x through nondegenerate triangles converging to x. We can also approximate the area of a portion of a smooth surface, through a slightly modified notion of area of inscribed triangular polyhedra approaching the surface (without any kind of constraint due to the Schwarz paradox)
Un sistema per la raccomandazione di risorse in una e-learning social network
No full textL’e-learning 2.0 ha ormai permeato tutte le realtà educative nazionali ed internazionali. La possibilità di contribuire attivamente al processo di costruzione della conoscenza per gli studenti è diventata fondamentale. È necessario, però,fornire strumenti tecnologici che supportino questi nuovi approcci cercando di guidare l’utente nella scelta delle risorse più opportune. Il lavoro propone una e-learning social network che, oltre ad offrire gli strumenti per la condivisione delle risorse, fornisce anche un modulo per la condivisione,descrizione e ricerca di Learning Object e un sistema di raccomandazione in grado di suggerire risorse (materiale didattico, gruppi di discussione, contatti) partendo da un insieme di tag utilizzati dagli utenti per descrivere i propri interessi e le risorse da condividere
Anneris Roselli, La chirurgia ippocratica. Saggio introduttivo e traduzioni
No full textJoly Robert. Anneris Roselli, La chirurgia ippocratica. Saggio introduttivo e traduzioni. In: L'antiquité classique, Tome 46, fasc. 1, 1977. p. 225
Un passo di giovanni Alessandrino su Tessalo (In Hipp. Epid. VI fr. 42, p. 104 Duffy = p. 148 Pritchet)
No full textIn a passage of the Commentary on Hippocrates Epidemics VI by John of Alexandria - an emblematical witness of Alexandrian Galenism - we can find traces of the popularity of astrological medicine in the commentator's times. John of Alexandria tries to counter it using - improperly - Galen's aggressive judgment on the Methodic physician Thessalus of Tralles
Exploring Italian olive oil consumers’ purchasing behaviour: Interactions between geographical indication and organic labels
No full textSince the first years of 90s, the European Union established two main quality schemes: geographical indications (GIs) and organic production (OP). Although, these two product categories still represent a small share of food market, quality certification schemes seems to sustain the food consumption pattern during the current economic crisis (ISMEA, 2014; ISMEAQualivita, 2017). There is a vast literature focusing on EU quality schemes applied to many food categories, including extra-virgin olive oil (EVOO) (e.g.: Scarpa & Del Giudice 2004; Aprile et al., 2012; Cicia et al., 2013; Di Vita et al., 2013; Carlucci et al., 2014; Panico et al. 2014; Del Giudice et al., 2015; Chinnici et al., 2016; Roselli et al., 2016; Boncinelli et al., 2017; Cavallo & Piqueras-Fiszman, 2017). However, in most of these studies GIs and OP have been separately analysed, under the assumption of independence. This paper aims to prove if there are some synergies between GIs and OP labels on olive oil products. Differently from previous studies, in this research the two certifications (GIs and OP) for olive oil products are simultaneously analysed while the independence from each other is checked. To reach this objective, the Italian olive oil consumers’ purchasing behaviour has been investigated through a survey involving a national representative sample of primary olive oil purchaser for household members
The convergence of a gesture recognizer and the shape of a plane gesture
No full textIn this work we provide the mathematical framework of !FTL, a new gesture
recognition algorithm. This allows us to algebraically quantify the notion of shape for a
smooth planar curve, inspired by the notion of shape of a triangle given previously by
Lester in this same journal. In particular, we approximate every gesture, considered as a
smooth planar curve, by a polygonal path inscribed on that curve. Then, we consider each
triple of consecutive points on that polygonal path as the vertices of a triangle having a
shape. We show that, as the polygonal line pointwise converges to the original gesture, the
corresponding sequence of shapes pointwise converges to a limiting curve of shapes, that we
consider to be the shape of that gesture. We use the Euclidean metric and the Riemann
integral to measure the distance between the shapes of two gestures. The position, scale and
rotation invariances of the shape of a triangle still hold for the shape of a gesture, and this
provides one of the main achievements of !FTL. Finally, we mention, for further research,
that the two dimensional Euclidean notion of shape can be extended to higher dimensional
settings and more general metrics using Clifford numbers
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