1,720,980 research outputs found
Deformation Spaces
No full textThe first instances of deformation theory were given by Kodaira and Spencer for complex structures and by Gerstenhaber for associative algebras. Since then, deformation theory has been applied as a useful tool in the study of many other mathematical structures, and even today it plays an important role in many developments of modern mathematics.
This volume collects a few self-contained and peer-reviewed papers by experts which present up-to-date research topics in algebraic and motivic topology, quantum field theory, algebraic geometry, noncommutative geometry and the deformation theory of Poisson algebras. They originate from activities at the Max-Planck-Institute for Mathematics and the Hausdorff Center for Mathematics in Bonn
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
Sheaf properties of the Higher Hochschild Homology
No full textNous montrons que le complexe de Hochschild supérieur associé à un ensemble simplicial pointé et connexe commute avec la localisation des algèbres commutatives sur un corps de caractéristique nulle. Après avoir défini la cohomologie de Hochschild supérieure d’un schéma, nous généralisons la suite spectrale de Hodge, le théorème HKR de Pirashvili, puis démontrons l’existence d’une décomposition de Hodge pour la cohomologie de Hochschild d’ordre supérieur d’un schéma lisse et séparé sur un corps de caractéristique nulle. Nous montrons que cette définition et la suite spectrale de Hodge coïncident avec la définition et la suite spectrale de Pirashvili dans le cas des ensembles simpliciaux pointés et connexes et des schémas affines. Nous définissons également une structure de modèle sur la catégorie des modules sur un préfaisceau de CDGA pour donner une définition équivalente de la cohomologie de Hochschild d’ordre supérieur d’un schéma séparé sur un corps de caractéristique nulle à coefficients dans un faisceau quasi-cohérent. Enfin, nous généralisons le théorème de Swan à la cohomologie de Hochschild des schémas séparés sur un corps.We show that the Higher Hochschild complex associated to a connected pointed simplicial set commutes with localization of commutative algebras over a field of characteristic zero. After defining the Higher Hochschild cohomology of a scheme, we generalize the Hodge spectral sequence, the HKR theorem of Pirashvili, and then show that there exists a Hodge decomposition for the higher order Hochschild cohomology of a separated smooth scheme over a field of characteristic zero. We show that this definition and the Hodge spectral sequence coincide with the definition and the spectral sequence of Pirashvili in the case of connected pointed simplicial sets and affine schemes. We also define a model structure on the category of modules over a presheaf of CDGA to give an equivalent definition of the higher order Hochschild cohomology of a separated scheme over a field of characteristic zero with coefficients in a quasi-coherent sheaf. Finally, we generalize the theorem of Swan to the Hochschild cohomology of separate schemes over a field
On pre-Calabi-Yau categories
No full textDans cette thèse, nous étudions les catégories de pré-Calabi-Yau et leurs morphismes.Nous développons pour cela un outil nous permettant de présenter les définitions et les preuves de manière plus simple, que nous appelons le calcul diagrammatique. Nous démontrons que le crochet perlé est un crochet de Lie d’une manière différente de celle utilisée dans la littérature existante, en le reliant au crochet de Gerstenhaber. En utilisant cette relation, nous explorons la relation entre les morphismes de pré-Calabi-Yau et les morphismes, étendant les résultats reliant les morphismes d’algèbres différentielles graduées de Poisson doubles et les morphismes. Ensuite, nous étudions la théorie de l’homotopie des morphismes de pré-Calabi-Yau, en les regardant en tant qu’éléments de Maurer-Cartan d’une certaine algèbre, et nous présentons les notions d’homotopie et d’homotopie faible. Nous complétons ensuite la relation entre les morphismes de pré-Calabi-Yau et les morphismes, prouvant que des morphismes de pré-Calabi-Yau homotopes donnent lieu à des A∞-morphismes faiblement homotopes. Par la suite, nous donnons de nouvelles preuves de diverses versions du Théorème de Transfert Homotopique pour les catégories de pré-Calabi-Yau, sans utiliser le calcul propéradique. Nous obtenons en conséquence l’existence des modèles minimaux des catégories de pré-Calabi-Yau et la quasi-inversibilité des quasi-isomorphismes. Finalement, nous étudions la théorie de l’obstruction des catégories de pré-Calabi-Yau et donnons ensuite une structure de modèle sans (co)limites pour la catégorie des algèbres de pré-Calabi-Yau.In this thesis, we study pre-Calabi-Yau categories and their morphisms.We develop for this a tool that allows us to present definitions and proofs in an easier way, that we call extbf diagrammatic calculus. By relating it with the Gerstenhaber bracket, we give a different proof than the existing one in the literature that the necklace bracket is a Lie bracket.Using this relation, we investigate the relation between pre-Calabi-Yau morphisms and morphisms, extending results relating morphims of dg double Poisson algebras and morphisms.Next, we study the homotopy theory of pre-Calabi-Yau morphisms, viewing them as Maurer-Cartan elements of a certain algebra, and present the notions of homotopy and weak homotopy. We then complete the relation between pre-Calabi-Yau morphisms and morphisms, proving that homotopic pre-Calabi-Yau morphisms give rise to weak homotopic morphisms.Afterwards, we give a new and direct proof of several variations of the Homotopy Transfer Theorem for pre-Calabi-Yau categories, without using properadic calculus. We obtain as a consequence that minimal models of pre-Calabi-Yau categories exist and that quasi-isomorphisms of pre-Calabi-Yau categories are quasi-invertible.Finally, we study the obstruction theory of pre-Calabi-Yau categories and then give a model structure without (co)limits on the category of pre-Calabi-Yau categories
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
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
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