Covering and packing in linear space

  • Authors:
  • Andreas Björklund;Thore Husfeldt;Petteri Kaski;Mikko Koivisto

  • Affiliations:
  • Lund University, Department of Computer Science, P.O. Box 118, SE-22100 Lund, Sweden;Lund University, Department of Computer Science, P.O. Box 118, SE-22100 Lund, Sweden and IT University of Copenhagen, Rued Langgaards Vej 7, 2300, København S, Denmark;Helsinki Institute for Information Technology HIIT, Aalto University, Department of Information and Computer Science, P.O. Box 15400, FI-00076 Aalto, Finland;Helsinki Institute for Information Technology HIIT, University of Helsinki, Department of Computer Science, P.O. Box 68, FI-00014 University of Helsinki, Finland

  • Venue:
  • Information Processing Letters
  • Year:
  • 2011

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Abstract

The fastest known algorithms for the k-cover and the k-packing problem rely on inclusion-exclusion and fast zeta transform, taking time and space 2^n, up to a factor polynomial in the size of the universe n. Here, we introduce a new, fast zeta transform algorithm that improves the space requirement to only linear in the size of the given set family, while not increasing the time requirement. Thus, for instance, the chromatic or domatic number of an n-vertex graph can be found in time within a polynomial factor of 2^n and space O(1.442^n) or O(1.716^n), respectively. For computing the chromatic polynomial, we further reduce the space requirement to O(1.292^n).