Vladimir Vovk’s contribution to the Discussion of ‘Safe testing’ by Grünwald, de Heide, and Koolen
Vladimir Vovk 对《安全检验》的讨论意见
The main result of this paper (Theorem 1) is elegant and satisfying, but in this comment I will concentrate on one of its limitations, namely the condition infW0D(Q‖PW0)<∞. (Analogous conditions are present in all generalizations given in the paper.) Even in the toy binary case with an infinite horizon, this condition is typically violated. Consider, e.g., the case of Markov alternative hypotheses Q considered in Ramdas et al. (2022): a nonIID Markov probability measure (or…