Calculating and interpreting the Mislin genus of a special class of nilpotent spaces

We prove that there is a bijection between the Mislin genus of a circle bundle over a certain nilpotent base space , which is constructed from a nilpotent group of a certain specified type, and the Mislin genus of itself.

     

Cosmological Solutions of Bi-metric Theories of Gravitation

The evidence in solar system tests of gravitation theories shows that in cosmological models the propagation velocities of gravitation and light may differ only by action of the local gravitational potential. The condition of approximately equal propagation velocities is shown to be consistent with cosmological models of some bi-metric tetrad theories. The way to analyze the situation is explained. We find a connection between the linear approximation of the theories with those properties of cosmological models, which are responsible for the local propagation of gravitation.     

Der Satz von Liebmann in Räumen konstanter Krümmung

Ohne Zusammenfassung     

Ein einfacher zugang zu neuartigen selenopyron- bzw. Selenopyrylium-derivaten aus β-chlor-propenyliden-immoniumsalzen und selen-nucleophilen

β-Amino-vinyl-selenoketones 9 react with aryl acetic acidchlorides 11, N-iminoformyl-arylacetic-imidchlorides 15 or derivatives of cyano acetic acid to give unknown 6-aryl-2-selenopyrones 14, 6-aryl-2-(N-formamidino)-selenopyrylium salts 16 or 6-aryl-2-amino-selenopyrylium salts 19. The compounds 19 were prepared from 3-(β-chloro-vinyl)-acrylonitriles 3 and NaHSe, too.     

Realization of Hardy's thought experiment with photons

We present an experimental realization of Hardy's thought experiment [Phys. Rev. Lett. 68, 2981 (1992)], using photons. The experiment consists of a pair of Mach-Zehnder interferometers that interact through photon bunching at a beam splitter. A striking contradiction is created between the predictions of quantum mechanics and local hidden variables. The contradiction relies on nonmaximally entangled position states of two particles. A Clauser-Horne-type inequality is derived and violated.