Published online by Cambridge University Press: 11 April 2013
In this paper we show that for every $n\geq 2$ there are minimal systems with perfect weakly mixing sets of order $n$ and all weakly mixing sets of order $n+ 1$ trivial. We present some relations between weakly mixing sets and topological sequence entropy; in particular, we prove that invertible minimal systems with non-trivial weakly mixing sets of order three always have positive topological sequence entropy. We also study relations between weak mixing of sets and other well-established notions from qualitative theory of dynamical systems like (regional) proximality, chaos and equicontinuity in a broad sense.