... Received July 4, 1998 We consider th e dynamica l system , which phas e space containe s a closed submanifold filled by periodi c orbits . ... Moreover, if eithe r th e fibration of A by closed orbit s is trivial , or th e base B = A=S^ of thi s fibration is locally fiat, the n th e numbe r of such orbit s is no t less tha n th e minima l numbe r of critical point s of smoot h function on th e quotien t manifold B. 1. ... Let A C M^ be a submanifold, filled by closed orbits of the unperturbed system...

147. INCIPIUNT CRONICA SLAVORUM EDITA A VENERABILI HELMOLDO PRESBITERO