eng
Schloss Dagstuhl – Leibniz-Zentrum für Informatik
Leibniz International Proceedings in Informatics
1868-8969
2012-02-24
613
623
10.4230/LIPIcs.STACS.2012.613
article
Trichotomy for Integer Linear Systems Based on Their Sign Patterns
Kimura, Kei
Makino, Kazuhisa
In this paper, we consider solving the integer linear systems, i.e.,
given a matrix A in R^{m*n}, a vector b in R^m, and a positive integer d, to compute an integer vector x in D^n such that Ax <= b,
where m and n denote positive integers, R denotes the set of reals, and D={0,1,..., d-1}. The problem is one of the most fundamental NP-hard problems in computer science.
For the problem, we propose a complexity index h which is based only on the sign pattern of A. For a real r, let ILS_=(r) denote the family of the problem instances I with h(I)=r. We then show the following trichotomy:
- ILS_=(r) is linearly solvable, if r < 1,
- ILS_=(r) is weakly NP-hard and pseudo-polynomially solvable, if r = 1, and
- ILS_=(r) is strongly NP-hard, if r > 1.
This, for example, includes the existing results that quadratic systems and Horn systems can be solved in pseudo-polynomial time.
https://drops.dagstuhl.de/storage/00lipics/lipics-vol014-stacs2012/LIPIcs.STACS.2012.613/LIPIcs.STACS.2012.613.pdf
Integer linear system
Sign pattern
Complexity index
TVPI system
Horn system