Weak but Not Strong Asymptotic Testability
arXiv:2607.26476
The paper constructs two disjoint families of stationary ergodic binary process distributions that admit a weakly asymptotically consistent test but no strongly asymptotically consistent test, thereby disproving the asymptotic‑consistency part of Ryabko’s conjecture.
Abstract
We construct two fixed disjoint families of stationary ergodic binary process distributions for which a weakly asymptotically consistent test exists, but no strongly asymptotically consistent test exists. The construction combines a synchronizing binary suspension code, an independent i.i.d marker process, and countably many independent slowly switching two-state Markov chains. In particular, this disproves the asymptotic-consistency branch of a conjecture of Ryabko.