On the Complexity of Generating Maximal Frequent and Minimal Infrequent Sets

  • Authors:
  • Endre Boros;Vladimir Gurvich;Leonid Khachiyan;Kazuhisa Makino

  • Affiliations:
  • -;-;-;-

  • Venue:
  • STACS '02 Proceedings of the 19th Annual Symposium on Theoretical Aspects of Computer Science
  • Year:
  • 2002

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Abstract

Let A be an m 脳 n binary matrix, t 驴 {1, ..., m} be a threshold, and 驴 0 be a positive parameter. We show that given a family of O(n驴) maximal t-frequent column sets for A, it is NP-complete to decide whether A has any further maximal t-frequent sets, or not, even when the number of such additional maximal t-frequent column sets may be exponentially large. In contrast, all minimal t-infrequent sets of columns of A can be enumerated in incremental quasi-polynomial time. The proof of the latter result follows from the inequality 驴 驴 (m-t+1)脽, where 驴 and 脽 are respectively the numbers of all maximal t-frequent and all minimal t-infrequent sets of columns of the matrix A. We also discuss the complexity of generating all closed t-frequent column sets for a given binary matrix.