Abstract:  We show that the q-derangement numbers satisfy a ratio monotone property, which is analogous to the log-concavity and is stronger than the spiral property and the unimodality.

  AMS Classification:  05A15, 05A16, 05A30.

  Keywords:  q-derangement number, spiral property, unimodality, log-concavity, ratio monotone property.

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