TOPICS
Search

Satisfiability Problem


The satisfiability problem asks whether a given Boolean formula in conjunctive normal form has an assignment that makes the formula "true." Cook (1971) showed that the problem is NP-complete.

Carenini (2026) announced existence of a limiting satisfiability threshold for every fixed clause size k>=3. In the model of independent uniformly signed clauses on k distinct variables, sampled with replacement, there is a finite positive alpha_k such that the probability of satisfiability with |_cn_| clauses tends to 1 for c<alpha_k and to 0 for c>alpha_k as the number n of variables tends to infinity. Here |_·_| is the floor function.

For random k-SAT with k=3, Vorobyev (2026) reported that a formula with n variables and |_4.268n_| clauses is unsatisfiable with probability tending to 1 as n->infty. This is an upper bound rather than an exact threshold. Vorobyev (2026) states that language models developed the mathematical argument, numerical code, and Lean formalization under the author's direction.


See also

3SAT, Boolean Algebra, Random k-SAT, Satisfiable

Explore with Wolfram|Alpha

References

Carenini, G. "A Polynomial Scaling Window for Random k-SAT and a Proof of the Satisfiability Conjecture." Electronic Colloquium on Computational Complexity, Report TR26-229, 2026. https://eccc.weizmann.ac.il/report/2026/229/.Cook, S. A. "The Complexity of Theorem-Proving Procedures." In Proc. Third Annual ACM Symposium on Theory of Computing. New York: Association for Computing Machinery, pp. 151-158, 1971. https://doi.org/10.1145/800157.805047.Cook, S. A. and Mitchell, D. G. "Finding Hard Instances of the Satisfiability Problem: A Survey." In Satisfiability Problem: Theory and Applications (Piscataway, NJ, 1996) (Ed. D. Du, J. Gu, and P. M. Pardalos). Providence, RI: Amer. Math. Soc., pp. 1-17, 1997.Vorobyev, F. "An Upper Bound of 4.268 for the Random 3-SAT Satisfiability Threshold." 6 Oct 2026. https://arxiv.org/abs/2610.10599.

Referenced on Wolfram|Alpha

Satisfiability Problem

Cite this as:

Weisstein, Eric W. "Satisfiability Problem." From MathWorld--A Wolfram Resource. https://mathworld.wolfram.com/SatisfiabilityProblem.html

Subject classifications