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On quasijet bundles

Tomáš, Jiří (2000)

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

In this paper a Weil approach to quasijets is discussed. For given manifolds M and N , a quasijet with source x M and target y N is a mapping T x r M T y r N which is a vector homomorphism for each one of the r vector bundle structures of the iterated tangent bundle T r [A. Dekrét, Casopis Pest. Mat. 111, No. 4, 345-352 (1986; Zbl 0611.58004)]. Let us denote by Q J r ( M , N ) the bundle of quasijets from M to N ; the space J ˜ r ( M , N ) of non-holonomic r -jets from M to N is embeded into Q J r ( M , N ) . On the other hand, the bundle Q T m r N of ( m , r ) -quasivelocities...

On sectioning multiples of the nontrivial line bundle over Grassmannians

Horanská, Ľubomíra (1998)

Proceedings of the 17th Winter School "Geometry and Physics"

Let G n , k ( G ˜ n , k ) denote the Grassmann manifold of linear k -spaces (resp. oriented k -spaces) in n , d n , k = k ( n - k ) = dim G n , k and suppose n 2 k . As an easy consequence of the Steenrod obstruction theory, one sees that ( d n , k + 1 ) -fold Whitney sum ( d n , k + 1 ) ξ n , k of the nontrivial line bundle ξ n , k over G n , k always has a nowhere vanishing section. The author deals with the following question: What is the least s ( = s n , k ) such that the vector bundle s ξ n , k admits a nowhere vanishing section ? Obviously, s n , k d n , k + 1 , and for the special case in which k = 1 , it is known that s n , 1 = d n , 1 + 1 . Using results...

On sectioning tangent bundles and other vector bundles

Korbaš, Július, Zvengrowski, Peter (1996)

Proceedings of the Winter School "Geometry and Physics"

This paper has two parts. Part one is mainly intended as a general introduction to the problem of sectioning vector bundles (in particular tangent bundles of smooth manifolds) by everywhere linearly independent sections, giving a survey of some ideas, methods and results.Part two then records some recent progress in sectioning tangent bundles of several families of specific manifolds.

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