On automorphisms for some fibered incidence groups

Summary In any kinematic space (with non trivial fibration) the group of all automorphisms of the geometric structure which preserve both parallelisms is shown to consist exactly of those automorphisms of the algebraic structure which preserve the fibration. Moreover a characterization of such group is given for a particular class of kinematic spaces. Research supported by the Italian Ministry of Education (40% M.P.I.).     

Convergence groups and seifert fibered 3-manifolds

Oblatum 22-VII-1992 & 11-I-1994     

Operators arising from representations of nilpotent Lie groups

The following two results are obtained for an irreducible multiplier representation T of a connected nilpotent Lie group. First, T_f is a Hilbert-Schmidt operator if f is square-integrable with compact support. Second, T_f is of trace class if f has derivatives with sufficiently many moments. An application is made of the latter result to show that T_f can be of trace class even when f is not continuous.     

Metrizably fibered generalized ordered spaces

In this paper we characterize generalized ordered spaces that are metrizably fibered in terms of certain quotient spaces and in terms of the existence of special open covers. We apply our results to give a new characterization of perfect generalized ordered spaces that have a σ-closed-discrete dense subset and to give examples of GO-spaces that are, or are not, metrizably fibered.     

Ergodic properties of fibered rational maps

We study the ergodic properties of fibered rational maps of the Riemann sphere. In particular we compute the topological entropy of such mappings and construct a measure of maximal relative entropy. The measure is shown to be the unique one with this property. We apply the results to selfmaps of ruled surfaces and to certain holomorphic mapping of the complex projective planeP ². Supported by the Swedish Foundation for International Cooperation in Research and Higher Education (STINT).     

Heegaard splittings of Seifert fibered spaces

Summary In this paper we give a classification theorem of genus two Heegaard splittings of Seifert fibered manifolds overS ² with three exceptional fibers, except for when two of the exceptional fibers hava the same invariants with opposite orientation.     

Asymptotic velocity for fibered Hamiltonians

We show the existence of the asymptotic velocity for a large class of Hamiltonians with a fibered structure.