A non-regular Toeplitz flow with preset pure point spectrum
Volume 120 / 1996
Studia Mathematica 120 (1996), 235-246 DOI: 10.4064/sm-120-3-235-246
Given an arbitrary countable subgroup $σ_0$ of the torus, containing infinitely many rationals, we construct a strictly ergodic 0-1 Toeplitz flow with pure point spectrum equal to $σ_0$. For a large class of Toeplitz flows certain eigenvalues are induced by eigenvalues of the flow Y which can be seen along the aperiodic parts.