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Equivalence problem for minimal rational curves with isotrivial varieties of minimal rational tangents

Jun-Muk Hwang (2010)

Annales scientifiques de l'École Normale Supérieure

We formulate the equivalence problem, in the sense of É. Cartan, for families of minimal rational curves on uniruled projective manifolds. An important invariant of this equivalence problem is the variety of minimal rational tangents. We study the case when varieties of minimal rational tangents at general points form an isotrivial family. The main question in this case is for which projective variety Z , a family of minimal rational curves with Z -isotrivial varieties of minimal rational tangents...

Equivariant cohomology of the skyrmion bundle

Gross, Christian (1997)

Proceedings of the 16th Winter School "Geometry and Physics"

The author constructs the gauged Skyrme model by introducing the skyrmion bundle as follows: instead of considering maps U : M SU N F he thinks of the meson fields as of global sections in a bundle B ( M , SU N F , G ) = P ( M , G ) × G SU N F . For calculations within the skyrmion bundle the author introduces by means of the so-called equivariant cohomology an analogue of the topological charge and the Wess-Zumino term. The final result of this paper is the following Theorem. For the skyrmion bundle with N F 6 , one has H * ( E G × G SU N F ) H * ( SU N F ) G S ( G ̲ * ) H * ( SU N F ) H * ( B G ) H * ( SU N F ) , where E G ( B G , G ) is the universal bundle...

Equivariant Embeddings of Differentiable Spaces

Rivas, R., González, J., De Salas, J. (2001)

Serdica Mathematical Journal

Given a differentiable action of a compact Lie group G on a compact smooth manifold V , there exists [3] a closed embedding of V into a finite-dimensional real vector space E so that the action of G on V may be extended to a differentiable linear action (a linear representation) of G on E. We prove an analogous equivariant embedding theorem for compact differentiable spaces (∞-standard in the sense of [6, 7, 8]).

Equivariant maps of joins of finite G-sets and an application to critical point theory

Danuta Rozpłoch-Nowakowska (1992)

Annales Polonici Mathematici

A lower estimate is proved for the number of critical orbits and critical values of a G-invariant C¹ function f : S n , where G is a finite nontrivial group acting freely and orthogonally on n + 1 0 . Neither Morse theory nor the minimax method is applied. The proofs are based on a general version of Borsuk’s Antipodal Theorem for equivariant maps of joins of G-sets.

Equivariant spectral triples

Andrzej Sitarz (2003)

Banach Center Publications

We present the review of noncommutative symmetries applied to Connes' formulation of spectral triples. We introduce the notion of equivariant spectral triples with Hopf algebras as isometries of noncommutative manifolds, relate it to other elements of theory (equivariant K-theory, homology, equivariant differential algebras) and provide several examples of spectral triples with their isometries: isospectral (twisted) deformations (including noncommutative torus) and finite spectral triples.

Ergodicity for a stochastic geodesic equation in the tangent bundle of the 2D sphere

Ľubomír Baňas, Zdzisław Brzeźniak, Mikhail Neklyudov, Martin Ondreját, Andreas Prohl (2015)

Czechoslovak Mathematical Journal

We study ergodic properties of stochastic geometric wave equations on a particular model with the target being the 2D sphere while considering only solutions which are independent of the space variable. This simplification leads to a degenerate stochastic equation in the tangent bundle of the 2D sphere. Studying this equation, we prove existence and non-uniqueness of invariant probability measures for the original problem and obtain also results on attractivity towards an invariant measure. We also...

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