The Weinstein Conjecture for Hamiltonian Fibrations

In this note we extend to non trivial Hamiltonian fibrations over symplectically uniruled manifolds a result of Lu's, \cite{Lu}, stating that any trivial symplectic product of two closed symplectic manifolds with one of them being symplectically uniruled verifies the Weinstein Conjecture for closed separating hypersurfaces of contact type, under certain technical conditions. The proof is based on the product formula for Gromov-Witten invariants ($GW$-invariant) of Hamiltonian fibrations derived in \cite{H}.Comment: 15 page

Invariants de Gromov-Witten et fibrations hamiltoniennes

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Irene Cheng, Charles Davis et Mabel Wilson (dir.), Race and Modern Architecture. A Critical history from the Enlightenment to the Present

Publié en décembre 2020, à la fin de la présidence de Trump, après une année agitée par les mouvements Black Lives Matter aux États-Unis comme en France et une crispation croissante des débats autour des questions d’identité, l’ouvrage Race and Modern Architecture sort au cœur d’une actualité brûlante. Il est le fruit d’un travail porté depuis 2015 par le groupe de recherche interdisciplinaire Race and Modern Architecture Project (R + MAP) et a vu son contenu déterminé par un symposium en 201..

Contact Hypersurfaces in Uniruled Symplectic Manifolds Always Separate

We observe that nonzero Gromov-Witten invariants with marked point constraints in a closed symplectic manifold imply restrictions on the homology classes that can be represented by contact hypersurfaces. As a special case, contact hypersurfaces must always separate if the symplectic manifold is uniruled. This removes a superfluous assumption in a result of G. Lu, thus implying that all contact manifolds that embed as contact type hypersurfaces into uniruled symplectic manifolds satisfy the Weinstein conjecture. We prove the main result using the Cieliebak-Mohnke approach to defining Gromov-Witten invariants via Donaldson hypersurfaces, thus no semipositivity or virtual moduli cycles are required.Comment: 24 pages, 1 figure; v.3 is a substantial expansion in which the semipositivity condition has been removed by implementing Cieliebak-Mohnke transversality; it also includes a new appendix to explain why the forgetful map in the Cieliebak-Mohnke context is a pseudocycle; v.4 has one short remark added; to appear in J. London Math. So

"Nous avons perdu notre lien à la nature" : le mythe de la faute des modernes ?

International audienceTaking as a starting point the loss of relation to nature of humans, the article put in question the idea that modernity would come out of an opposition between nature and culture by analyzing the writings of modern designers and artists. Does the sensation of loss of connection with nature comes from the contempt of the living that had the men who shaped modernity, or from their discrediting of the cultural representation of nature of other social groups ?Prenant comme point de départ la perte de relation à la nature des humains, l'article propose de remettre en question l'idée que la modernité découlerait nécessairement d'une opposition entre nature et culture en examinant les écrits d'architectes et designers modernes,. La sensation de perte de lien avec la nature découlerait-elle d'un avéré mépris du vivant des hommes ayant façonné la modernité, ou de leur déconsidération de représentations culturelles de la nature de groupes sociaux autres que le leur

Introduction - De quoi la nature est-elle le nom ?

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