On new spectral multiplicities for ergodic maps
Tom 197 / 2010
Studia Mathematica 197 (2010), 57-68 MSC: 37A05, 37A30. DOI: 10.4064/sm197-1-5
It is shown that each subset of positive integers that contains 2 is realizable as the set of essential values of the multiplicity function for the Koopman operator of some weakly mixing transformation.