Patent ID: 8732117

Claim:
An information processing apparatus comprising a processor configured to perform a procedure including: (a) deleting, from a plurality of sets each including at least one element and stored in a storage unit, a set having less than a threshold number of included elements and an element existing in only sets whose number is less than a threshold number of occurrences repeatedly and alternately until there is no set or element that needs to be deleted; (b) generating, out of sets remaining in the storage unit after the deleting of the set and element, a group to which sets associated with each other in terms of commonality of elements belong; (c) deleting, with respect to each of generated groups stored in the storage unit, a set having less than the threshold number of included elements and an element existing in only sets whose number in a same group is less than the threshold number of occurrences, from the sets belonging to said each group repeatedly and alternately until there is no set or element that needs to be deleted; and (d) outputting a list of elements included in sets remaining in said each group subjected to the deleting of the set and element.