match finds the positions of first matches of a collection of
sequences or sequence rules in an object of the same class.
%in% indicates matches of the left in the right operand.
If the right operand is a vector of item labels indicates if a
sequence contains any of the items given.
%ain% indicates if a sequence contains all the items given as
the right operand.
%pin% indicates if a sequence contains any item matching
the regular expression given as the right operand.
%ein% indicates if a sequence contains any itemset
containing all the items given as the right operand.
duplicated indicates duplicate occurrences of sequences
or sequence rules.