Maximale Strömungen vollergodischer Automorphismen mit quasidiskretem Spektrum

Abstract

Every totally ergodic automorphism with quasi-discrete spectrum on a Lebesgue space can be embedded in a maximal discrete flow which is generated by all roots of the automorphism. It is also shown that for every subgroup of the additive group of the rationals and every natural $n$ a totally ergodic automorphism with quasidiscrete spectrum exists which Halmos-invariant is equal to $n$ and which can be embedded in a discrete flow which parametergroup is the given subgroup of the rationals.