Tree for the set = {aaa, aac, aca, acc, cct} with dashed links for δ function under Markov(1) model. Tree for the set = {AAA, AAC, ACA, ACC, CCT} under Markov model of order 1. Dashed colored links represent δ function for internal node (8) – in red, and for marked node (10) corresponding to the word AAC ∈ – in purple.