arXiv subjects

Jan Slovak

Publications and source records attributed to Jan Slovak.

20 records · Page 2Linked to original sources

arXiv1996

Invariant operators on manifolds with almost Hermitian symmetric structures, II. Normal Cartan connections

In the first part of this series of papers we developed the invariant differentiation with respect to a Cartan connection, we described this procedure in the terms of the underlying principal connections, and we discussed applications of this theory to the construction of natural operators. In this part we will extend the results of \cite{Ochiai, 70} on the existence and the uniqueness of the so called normal Cartan connections on manifolds with almost Hermitian symmetric structures to first order structures which do not admit a torsion free linear connection. Moreover, for each of these structures we obtain explicit (universal) formulae for these canonical connections in the terms of the curvatures of the underlying linear connections.

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arXiv1994

On multilinear operators commuting with Lie derivatives

Let $E_1,\dots ,E_k$ and $E$ be natural vector bundles defined over the category $\Cal Mf_m^+$ of smooth oriented $m$--dimensional manifolds and orientation preserving local diffeomorphisms, with $m\geq 2$. Let $M$ be an object of $\Cal Mf_m^+$ which is connected. We give a complete classification of all separately continuous $k$--linear operators $D\:\Ga _c(E_1M)\x\dots\x\Ga_c(E_kM)\to \Ga (EM)$ defined on sections with compact supports, which commute with Lie derivatives, iė\. which satisfy $$ \Cal L_X(D(s_1,\dots ,s_k))=\sum _{i=1}^kD(s_1,\dots ,\Cal L_Xs_i,\dots,s_k), $$ for all vector fields $X$ on $M$ and sections $s_j\in\Ga_c(E_jM)$, in terms of local natural operators and absolutely invariant sections. In special cases we do not need the continuity assumption. We also present several applications in concrete geometrical situations, in particular we give a completely algebraic characterization of some well known Lie brackets.

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