Abstract
k-SAT is a fundamental constraint satisfaction problem. It involves S(m), the satisfaction set of the conjunction of m clauses, each clause a disjunction of k literals. The problem has many theoretical, algorithmic and practical aspects. When the clauses are chosen at random it is anticipated (but not fully proven) that, as the density parameter m/n (n the number of variables) grows, the transition of S(m) to being empty, is abrupt: It has a "sharp threshold", with probability 1 - o(1). In this articlewe replace the random ensemble analysis by a pseudo-random one: Derive the decay rule for individual sequences of clauses, subject to combinatorial conditions, which in turn hold with probability 1 - o(1). This is carried out under the big relaxation that k is not constant but k = γ log n, or even r log log n. Then the decay of S is slow, "near-perfect" (like a radioactive decay), which entails sharp thresholds for the transition-time of S below any given level, down to S = 0.
| Original language | English |
|---|---|
| Pages (from-to) | 815-825 |
| Number of pages | 11 |
| Journal | Logic Journal of the IGPL |
| Volume | 14 |
| Issue number | 5 |
| DOIs | |
| State | Published - Oct 2006 |
Keywords
- Constraint satisfaction
- Learning from examples
- Pseudorandom analysis
- Sharp thresholds
- Unique k-SAT representations
- k-SAT