Rule generation How to efficiently generate rules from frequent itemsets? In general,confidence does not have an anti- monotone property c(ABC→D)can be larger or smaller than c(AB→D) But confidence of rules generated from the same itemset has an anti-monotone property -e.g.,L=(A,B,C,D): c(ABC→D)2c(AB→CD)≥c(A→BCD) Confidence is anti-monotone w.r.t.number of items on the RHS of the rule ATA 8 Copyright 2019 by Xiaoyu Li.8 Copyright © 2019 by Xiaoyu Li. Rule Generation