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On the rigidity of webs

Michel Belliart (2007)

Bulletin de la Société Mathématique de France

Plane d -webs have been studied a lot since their appearance at the turn of the 20th century. A rather recent and striking result for them is the theorem of Dufour, stating that the measurable conjugacies between 3-webs have to be analytic. Here, we show that even the set-theoretic conjugacies between two d -webs, d 3 are analytic unless both webs are analytically parallelizable. Between two set-theoretically conjugate parallelizable d -webs, however, there always exists a nonmeasurable conjugacy; still,...

On the role of partial Ricci curvature in the geometry of submanifolds and foliations

Vladimir Rovenskiĭ (1998)

Annales Polonici Mathematici

Submanifolds and foliations with restrictions on q-Ricci curvature are studied. In §1 we estimate the distance between two compact submanifolds in a space of positive q-Ricci curvature, and give applications to special classes of submanifolds and foliations: k-saddle, totally geodesic, with nonpositive extrinsic q-Ricci curvature. In §2 we generalize a lemma by T. Otsuki on asymptotic vectors of a bilinear form and then estimate from below the radius of an immersed submanifold in a simply connected...

On the second order absolute differentiation

Cabras, Antonella, Kolář, Ivan (1999)

Proceedings of the 18th Winter School "Geometry and Physics"

In this paper the authors compare two different approaches to the second order absolute differentiation of a fibered manifold (one of them was studied by the authors [Arch. Math., Brno 33, 23-35 (1997; Zbl 0910.53014)]. The main goal is the extension of one approach to connections on functional bundles of all smooth maps between the fibers of two fibered manifolds over the same base (we refer to the book “Natural Operations in Differential Geometry” [Springer, Berlin (1993; Zbl 0782.53013)] I. Kolar,...

On the short time asymptotic of the stochastic Allen–Cahn equation

Hendrik Weber (2010)

Annales de l'I.H.P. Probabilités et statistiques

A description of the short time behavior of solutions of the Allen–Cahn equation with a smoothened additive noise is presented. The key result is that in the sharp interface limit solutions move according to motion by mean curvature with an additional stochastic forcing. This extends a similar result of Funaki [Acta Math. Sin (Engl. Ser.)15 (1999) 407–438] in spatial dimension n=2 to arbitrary dimensions.

On the simplicial structure of some Weil bundles

Kureš, Miroslav (2000)

Proceedings of the 19th Winter School "Geometry and Physics"

The author considers the problem to give explicit descriptions for several types of bundles on smooth manifolds, naturally related with the bundle of k -dimensional velocities, or k -jets. In fact, this kind of bundles are very natural objects in differential geometry, mechanics and Lagrangian dynamics. For this the author considers Weil bundles that arose from Weil algebras. If a suitable combinatorial data is provided by a simplicial coloured structure, then the author describes the corresponding...

On the space of maps inducing isomorphic connections

T. R. Ramadas (1982)

Annales de l'institut Fourier

Let ω be the universal connection on the bundle E U ( n ) B U ( n ) . Given a principal U ( n ) -bundle P M with connection A , we determine the homotopy type of the space of maps ϕ of M into B U ( n ) such that ( ϕ + E U ( n ) , ϕ + ω ) is isomorphic to ( P , A ) . Here ϕ + denotes pull-back.

Currently displaying 1001 – 1020 of 1190