1,721,119 research outputs found
Schur functors and motives
Full text linkIn this article we study the class of Schur-finite motives, that is, motives which
are annihilated by a schur functor. We compare this notion to a similar one due to Kimura. In particular, we show that the motive of any curve is Kimura-finite. This last result
has also been obtained by V. Guletski ̆ı. We conclude with an example by O’Sullivan of
a non-Kimura-finite motive which is Schur-finite
Biextensions and 1-motives
Full text linkThe notion of biextension of two abelian groups by another abelian group is a classical one coming from [SGA7, VII], later extended by Deligne in [D, 10.2] to the case where K0 and K1 are two complexes of abelian sheaves and H is another abelian sheaf. His result Biext1 (K1 , K2 ; H) ∼ Ext1 (K1 ⊗L K2 , H) suggests that the biextension of two 1-motives is related to their tensor product, which is outside the category of 1-motives for trivial reasons
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
Lectures notes on motivic cohomology
No full textThis is a much-welcomed text on the motivic cohomology theory of Suslin and Voevodsky, based on lectures given by Voevodsky. Its main contents are the definition of motivic cohomology, the (derived) category of motives, and the proofs of several basic theorems on motivic cohomology.
The first two-thirds of the book is self-contained and should be accessible to graduate students with some background in algebraic geometry, intersection theory, and homological algebra. This part begins with the definition of presheaves with transfers and motivic cohomology, and the proof that Z(1)≅O×[−1], and that Hn,n(K,Z)≅KMn(F). Then, étale sheaves with transfers, Nisnevich sheaves with transfers, the tensor triangulated categories DMeff,−Nis(k) and DMeff,−ét(k) and their properties are discussed. As an application, étale motivic cohomology with finite coefficients prime to the characteristic of the base field is identified with usual étale cohomology, and shown to be the dual of Suslin's singular homology. Supplemental material on finite correspondences, the Nisnevich topology, and tensor triangulated categories is also provided.
The last third of the book is more technical. It is devoted to the proof that motivic cohomology agrees with higher Chow groups for smooth schemes, and to the proof of the basic theorem (used before) that over a perfect field, a homotopy invariant presheaf with transfers has homotopy invariant Nisnevich cohomology, and admits a Gersten resolution
Strade a perdere. La storia a bivi di una generazione, recensione a C. Mazza Galanti, Cosa pensavi di fare? Romanzo a bivi per umanisti sul lastrico
No full textrecensione del romanzo di C. Mazza Galanti, Cosa pensavi di fare? Romanzo a bivi per umanisti sul lastrico (Milano, Il Saggiatore, 2020), testo narrativo che si distingue per l'originalità della forma, configurandosi come un'opera di taglio generazionale scritta secondo la modalità del libro-gioco a biv
Valutazione clinica di una associazione Tobramicina 0.3% e Desametazone 0.1% in collirio nel trattamento delle flogosi oculari post-intervento di cataratta con tecnica di facoemulsificazione.
No full textSi valuta una associazione Tobramicina 0.3% e Desametazone 0.1% in collirio nel trattamento delle flogosi oculari post-intervento di cataratta con tecnica di facoemulsificazione
- …
