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 a basis in terms of the -action on the type fiber of the concerned bundle, where denotes the kernel of the projection of the jet group onto the jet group [see I. Kolár, P. Michor and J. Slovák, ‘Natural operations in differential geometry’ (Springer-Verlag, Berlin) (1993; Zbl 0782.53013) or D. Krupka, Loc!
@article{701655, title = {Natural operators on frame bundles}, booktitle = {Proceedings of the 19th Winter School "Geometry and Physics"}, series = {GDML\_Books}, publisher = {Circolo Matematico di Palermo}, address = {Palermo}, year = {2000}, pages = {121-129}, mrnumber = {MR1758087}, zbl = {0971.58002}, url = {http://dml.mathdoc.fr/item/701655} }
Krupka, Michal. Natural operators on frame bundles, dans Proceedings of the 19th Winter School "Geometry and Physics", GDML_Books, (2000), pp. 121-129. http://gdmltest.u-ga.fr/item/701655/