Natural liftings of -tensor fields to the tangent bundle
We determine all first order natural operators transforming –tensor fields on a manifold into –tensor fields on .
We determine all first order natural operators transforming –tensor fields on a manifold into –tensor fields on .
Let be a -dimensional foliation on an -manifold , and the -tangent bundle of . The purpose of this paper is to present some reltionship between the foliation and a natural lifting of to the bundle . Let
A classification of natural liftings of foliations to the tangent bundle is given.
Natural liftings are classified for . It is proved that they form a 5-parameter family of operators.
The authors study some geometrical constructions on the cotangent bundle from the viewpoint of natural operations. First they deduce that all natural operators transforming functions on into vector fields on are linearly generated by the Hamiltonian vector field with respect to the canonical symplectic structure of and by the Liouville vector field of . Then they determine all natural operators transforming pairs of functions on into functions on . In this case, the main generator is...
[For the entire collection see Zbl 0742.00067.]This paper is devoted to a method permitting to determine explicitly all multilinear natural operators between vector-valued differential forms and between sections of several other natural vector bundles.
We prove, that -th order gauge natural operators on the bundle of Cartan connections with a target in the gauge natural bundles of the order (“tensor bundles”) factorize through the curvature and its invariant derivatives up to order . On the course to this result we also prove that the invariant derivations (a generalization of the covariant derivation for Cartan geometries) of the curvature function of a Cartan connection have the tensor character. A modification of the theorem is given for...
For natural numbers n ≥ 3 and r ≥ 1 all natural operators transforming functions from n-manifolds into affinors (i.e. tensor fields of type (1,1)) on the r-cotangent bundle are classified.
The complete description of all natural operators lifting real valued functions to bundle functors on fibered manifolds is given. The full collection of all natural operators lifting projectable real valued functions to bundle functors on fibered manifolds is presented.
The author studies the problem how a map on an -dimensional manifold can induce canonically a map for a fixed natural number. He proves the following result: “Let be a natural operator for -manifolds. If then there exists a uniquely determined smooth map such that .”The conclusion is that all natural functions on for -manifolds are of the form , where is a function of variables.
The author proves that for a manifold of dimension greater than 2 the sets of all natural operators and , respectively, are free finitely generated -modules. The space , this is, jets with target 0 of maps from to , is called the space of all -covelocities on . Examples of such operators are shown and the bases of the modules are explicitly constructed. The definitions and methods are those of the book of I. Kolář, P. W. Michor and J. Slovák [Natural operations in differential geometry,...
Let be a Weil algebra. The bijection between all natural operators lifting vector fields from -manifolds to the bundle functor of Weil contact elements and the subalgebra of fixed elements of the Weil algebra is determined and the bijection between all natural affinors on and is deduced. Furthermore, the rigidity of the functor is proved. Requisite results about the structure of are obtained by a purely algebraic approach, namely the existence of nontrivial is discussed.
Let be a natural bundle of order ; a basis of the -th order differential operators of with values in -th order bundles is an operator of that type such that any other one is obtained by composing with a suitable zero-order operator. In this article a basis is found in the following two cases: for (semi-holonomic -th order frame bundle), , and (-st order frame bundle), . The author uses here the so-called method of orbit reduction which provides one with a criterion for checking...
Let be a fibered manifold over a manifold and be a homomorphism between Weil algebras and . Using the results of Mikulski and others, which classify product preserving bundle functors on the category of fibered manifolds, the author classifies all natural operators , where denotes the space of projective vector fields on and the bundle functors associated with .
Let us consider two closed surfaces , of class and two functions , of class , called measuring functions. The natural pseudodistance between the pairs , is defined as the infimum of as varies in the set of all homeomorphisms from onto . In this paper we prove that the natural pseudodistance equals either , , or , where and are two suitable critical values of the measuring functions. This shows that a previous relation between the natural pseudodistance and critical values...
In this nice paper the author proves that all natural symplectic forms on the tangent bundle of a pseudo-Riemannian manifold are pull-backs of the canonical symplectic form on the cotangent bundle with respect to some diffeomorphisms which are naturally induced by the metric.