EN
CONTENTS
Introduction............................................................................5
1. The main ideas and results................................................6
2. $H^{n,k}$-invariant subsets of $ℋ^{n,k}$.........................22
3. Reduction to germs of differential 1-forms........................35
4. The case k ≥ 2n-3. Proof of Theorem A...........................44
5. The case n = 3, k = 2.......................................................46
Appendix. Connections with control theory...........................59
List of symbols......................................................................61
References..........................................................................63
References to the Appendix.................................................63