1,720,997 research outputs found
Hilbert e i fondamenti della geometria (1891-1902)B
No full textHilbert's epoch-making Grundlagen der Geometrie (GG) (1899) had a tremendous impact on the development of both logic and axiomatic thought, as discussed by Mangione in vol. 5 of Geymonat's Storia del pensiero scientifico e filosofico. Leaving this on the background, the present paper focuses instead on the origins and development of Hilbert's ideas on the foundations of geometry, and compares them with the contemporary work by Italian mathematicians. In fact, GG was the eventual outcome of a long-term research pursued by Hilbert over a decade, and presented in his courses at Koenigsberg and Goettingen. Eventually, its influence can be recognised in some of his celebrated 'mathemtical problems' (ICM Paris, 1900)
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
tempo fisico e movimento
No full textSi mostra come la fisica non sia in grado di rappresentare adeguatamente il movimento. In particolare si esamina il rapporto fra la serie A e la serie B con le teorie relativistiche
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
Un approccio categoriale ai flussi di informazione quantistica
No full textIn strongly compact closed category with biproducts many crucial features of quantum computing in Hilbert spaces have been recently recasted: the additive level describes the irreversible process of measure and allows to model the classical information flow during a quantum information protocol. In this paper we suggest to grasp the different
situations occurring in quantum information theory where the input output systems of an information channel can be either quantum or classical only on the base of the multiplicative level of the category. The aim of our approach is not restricted to a formalization of the standard
Hilbert space point of view, but intends to gain a more operational meaning. More precisely, we analyze the conditions on the monoids of the category which allow to recover a categorical version of the notion
of C*-algebras acting on a Hilbert space and which will be subject to a precise valutation regarding the no-cloning principle. We find that the elements of the monoid invariant with respect to the action of the cloning form exactly a commutative subalgebra, the categorical structure
for a classical object
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