“…One of the defects in frequent pattern mining is that there are abundant redundant patterns in the very large number of output patterns [22]. As a result, how to effectively reduce redundancy of the output becomes an essential problem of current research [23,13,11,18,16,10,6,8]. Frequent episode mining [14] (FEM for short), as one of the sub-topics of frequent pattern mining, which aims at discovering frequently appeared ordered sets of events from a single symbol (event) sequence, is facing the similar problem as well.…”