An undecidable problem for countable markov chains

A nondeterministic defense system is considered for a linearly ordered sequences of nodes of a countable Markov chain with an environment. We prove undecidability of the problem of existence of a sequence of signals from attacking subsystems that render the central nodes completely defenseless.Translated from Kibernetika, No. 2, pp. 1–6, 15, March–April, 1991.