We show that for any irrational number α and a sequence of integers such that , there exists a continuous measure μ on the circle such that . This implies that any rigidity sequence of any ergodic transformation is a rigidity sequence for some weakly mixing dynamical system. On the other hand, we show that for any α ∈ ℝ - ℚ, there exists a sequence of integers such that and such that is dense on the circle if and only if θ ∉ ℚα + ℚ.
@article{bwmeta1.element.bwnjournal-article-doi-10_4064-aa165-4-2, author = {Bassam Fayad and Jean-Paul Thouvenot}, title = {On the convergence to 0 of mnxmod 1}, journal = {Acta Arithmetica}, volume = {166}, year = {2014}, pages = {327-332}, zbl = {1310.11079}, language = {en}, url = {http://dml.mathdoc.fr/item/bwmeta1.element.bwnjournal-article-doi-10_4064-aa165-4-2} }
Bassam Fayad; Jean-Paul Thouvenot. On the convergence to 0 of mₙξmod 1. Acta Arithmetica, Tome 166 (2014) pp. 327-332. http://gdmltest.u-ga.fr/item/bwmeta1.element.bwnjournal-article-doi-10_4064-aa165-4-2/