Fundamentalsätze der metrischen Geometrie

For arbitrary quadratic forms, including the cases of characteristic 2 and of infinite dimensions, several affine-metric and projective-metric structures are considered, and the corresponding isomorphisms are determined. As an application, a general fundamental theorem of the miquelian circle geometry is proved.

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Martin Barner zum 65. Geburtstag gewidmet     

Pairwise sufficiency

Summary For an arbitrary experiment E we investigate the relation between its pairwise sufficient subalgebras and its sufficient sublattices in the M-space of E (in the sense of L. LeCam). By exhibiting an experiment without minimal pairwise sufficient subalgebra it is shown that this correspondence is in general not bijective. In view of this we introduce the rather large class of majorized experiments. They have a minimal pairwise sufficient subalgebra which can be described explicitely.As a natural subclass of the majorized experiments appear the coherent experiments that are distinguished by the coincidence of sufficiency and pairwise sufficiency. It is shown that the coherent experiments are characterized by the fact that they admit a majorizing measure which is localizable. As a consequence we obtain that the class of coherent experiments coincides with classes of experiments previously introduced by T.S. Pitcher, D. Mußmann, M. Hasegawa and M.D. Perlman.     

Kazhdan constants and the dual space topology

Supported by NATO collaborative research grant CRG 900029     

Static hyperon properties in a linearizedSU(3)-Chiral Bag model

We use a linearized Chiral Bag model to describe the strange octet and decuplet baryons. The approach is canonically extended to spontaneously broken chiral SU(3)_L × SU(3)_R, and the corresponding Goldstone Bosons are identified with the pseudoscalar meson octet. We include explicit symmetry breaking corrections both for baryons and mesons. The linearized quark-meson intraction is applied in a self-consistent calculation of the masses and, for Δ, Σ^* and Ξ^*, of the decay widths. Our special interest is in the influence of theK- andη-cloud (in addition to theπ) on hyperon static properties. We show results for radii, masses, decay widths and renormalization constants as obtained by a fit to the experimental hyperon spectra. The effects of theK- andη-mesons are found to be non-negligible, although supressed by symmetry breaking effects. The effective gluon coupling α is reduced in comparison to the SU(2)_L × SU(2)_R case. In addition, we discuss the dependence on the bag constantB. It turns out that the lightest hyperon states, Λ and Σ are well described and stable for B^1/4 < 130 MeV. The heavier strange baryons have stable solutions also for larger values ofB. The bag radii determined at the minimal energies are R₀?1.15 fm for the octet and R₀?1.25 fm for the decuplet baryons.