A useful theorem of Kuˇcera states that given a Martin-L¨of random infinite binary sequence ω and an effectively open set A of measure less than 1, some tail of ω is not in A. We show that this result can be seen as an effective version of Birkhoff’s ergodic theorem (in a special case). We prove several results in the same spirit and generalize them via an effective ergodic theorem for bijective ergodic maps.
Laurent Bienvenu, Adam R. Day, Ilya Mezhirov, Alex