Published online by Cambridge University Press: 30 November 2017
Given a sequence (M k , Q k )k ≥ 1 of independent and identically distributed random vectors with nonnegative components, we consider the recursive Markov chain (X n )n ≥ 0, defined by the random difference equation X n = M n X n - 1 + Q n for n ≥ 1, where X 0 is independent of (M k , Q k )k ≥ 1. Criteria for the null recurrence/transience are provided in the situation where (X n )n ≥ 0 is contractive in the sense that M 1 ⋯ M n → 0 almost surely, yet occasional large values of the Q n overcompensate the contractive behavior so that positive recurrence fails to hold. We also investigate the attractor set of (X n )n ≥ 0 under the sole assumption that this chain is locally contractive and recurrent.