Partitioning
Will any large itemsets be missed?
If l ? Li, then t1(l)/t1 < MS & t2(l)/t2 < MS & … & tn(l)/tn < MS, and t1(l) < MS*t1 & t2(l) < MS*t2 & … & tn(l) < MS*tn, thus t1(l) + t2(l) + … + tn(l) < MS * (t1 + t2 + … + tn)
t1 + t2 + … + tn is total #transactions, t1(l) + t2(l) + … + tn(l) is #transactions containing l, so support(l) < MS and l ? L