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La neige est blanche ssi... Prédication et perception

Jean Petitot (1997)

Mathématiques et Sciences Humaines

L'article traite des liens entre la syntaxe et la sémantique formelle (de nature logique) des jugements perceptifs et leur contenu proprement perceptif (de nature géométrique). Dans les situations les plus élémentaires le contenu perceptif se ramène à des remplissements de domaines spatiaux (l'extension des objets) par des qualités sensibles (couleurs, textures, etc.). Ces remplissements sont descriptibles par des sections de fibrations appropriées, qui sont des cas particuliers de faisceaux. Il...

Left-Garside categories, self-distributivity, and braids

Patrick Dehornoy (2009)

Annales mathématiques Blaise Pascal

In connection with the emerging theory of Garside categories, we develop the notions of a left-Garside category and of a locally left-Garside monoid. In this framework, the relationship between the self-distributivity law LD and braids amounts to the result that a certain category associated with LD is a left-Garside category, which projects onto the standard Garside category of braids. This approach leads to a realistic program for establishing the Embedding Conjecture of [Dehornoy, Braids and...

Lifting D -modules from positive to zero characteristic

João Pedro P. dos Santos (2011)

Bulletin de la Société Mathématique de France

We study liftings or deformations of D -modules ( D is the ring of differential operators from EGA IV) from positive characteristic to characteristic zero using ideas of Matzat and Berthelot’s theory of arithmetic D -modules. We pay special attention to the growth of the differential Galois group of the liftings. We also apply formal deformation theory (following Schlessinger and Mazur) to analyze the space of all liftings of a given D -module in positive characteristic. At the end we compare the problems...

Linear programming duality and morphisms

Winfried Hochstättler, Jaroslav Nešetřil (1999)

Commentationes Mathematicae Universitatis Carolinae

In this paper we investigate a class of problems permitting a good characterisation from the point of view of morphisms of oriented matroids. We prove several morphism-duality theorems for oriented matroids. These generalize LP-duality (in form of Farkas' Lemma) and Minty's Painting Lemma. Moreover, we characterize all morphism duality theorems, thus proving the essential unicity of Farkas' Lemma. This research helped to isolate perhaps the most natural definition of strong maps for oriented matroids....

Linking the closure and orthogonality properties of perfect morphisms in a category

David Holgate (1998)

Commentationes Mathematicae Universitatis Carolinae

We define perfect morphisms to be those which are the pullback of their image under a given endofunctor. The interplay of these morphisms with other generalisations of perfect maps is investigated. In particular, closure operator theory is used to link closure and orthogonality properties of such morphisms. A number of detailed examples are given.

Local analytic rings

Jorge C. Zilber (1990)

Cahiers de Topologie et Géométrie Différentielle Catégoriques

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