“…If R k is really infinite then t k is total and so f (e) ≥ t k (e) for some (infinitely many) e. So we define D e,k to consist of the first h( e, k ) elements of R k , if any, as found during a search time of f ( e, k ) or even just f (e). By Corollary 7 and Theorem 11, the dualism between immunity and pandemics is the same, Muchnik-degree-wise, as that between, in the notation of Brendle et al [7], -eventually different functions, b( = * ), and functions that are infinitely often equal to each recursive function, d( = * ). Remark 1.…”