  This paper is concerned with relationships of weakly mixing, topologically
weakly mixing, and sensitivity for non-autonomous discrete systems. It is shown
that weakly mixing implies topologically weakly mixing and sensitivity for
measurable systems with a fully supported measure; and topological weakly
mixing implies sensitivity for general dynamical systems. However, the inverse
conclusions are not true and some counterexamples are given. The related
existing results for autonomous discrete systems are generalized to
non-autonomous discrete systems and their conditions are weaken.
