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The QSAT problem is the quantified version of the SAT problem. We show the existence of a threshold effect for the phase transition associated with the satisfiability of random quantified extended 2-CNF formulas. We consider boolean CNF…

Discrete Mathematics · Computer Science 2009-07-07 Nadia Creignou , Herve Daude , Uwe Egly , Raphael Rossignol

We call a CNF formula linear if any two clauses have at most one variable in common. Let m(k) be the largest integer m such that any linear k-CNF formula with <= m clauses is satisfiable. We show that 4^k / (4e^2k^3) <= m(k) < ln(2) k^4…

Discrete Mathematics · Computer Science 2008-07-10 Dominik Scheder

Let $\varPhi$ be a uniformly distributed random $k$-SAT formula with $n$ variables and $m$ clauses. For clauses/variables ratio $m/n \leq r_{k\text{-SAT}} \sim 2^k\ln2$ the formula $\varPhi$ is satisfiable with high probability. However, no…

Data Structures and Algorithms · Computer Science 2016-03-01 Samuel Hetterich

We present a new structural (or syntatic) approach for estimating the satisfiability threshold of random 3-SAT formulae. We show its efficiency in obtaining a jump from the previous upper bounds, lowering them to 4.506. The method combines…

Discrete Mathematics · Computer Science 2007-05-23 Olivier Dubois , Yacine Boufkhad , Jacques Mandler

We show that the CNF satisfiability problem (SAT) can be solved in time $O^*(1.1199^{(d-2)n})$, where $d$ is either the maximum number of occurrences of any variable or the average number of occurrences of all variables if no variable…

Data Structures and Algorithms · Computer Science 2024-11-13 Sanjay Jain , Tzeh Yuan Neoh , Frank Stephan

By the MAXSAT problem, we are given a set $V$ of $m$ variables and a collection $C$ of $n$ clauses over $V$, i.e., a conjunctive normal form ($\textit{CNF}$) formula. We will seek a truth assignment to maximize the number of satisfied…

Computational Complexity · Computer Science 2025-08-05 Yangjun Chen

It is well known that there is a sharp density threshold for a random $r$-SAT formula to be satisfiable, and a similar, smaller, threshold for it to be satisfied by the pure literal rule. Also, above the satisfiability threshold, where a…

Discrete Mathematics · Computer Science 2010-08-09 Alexander D. Scott , Gregory B. Sorkin

For a $k$-ary predicate $P$, a random instance of CSP$(P)$ with $n$ variables and $m$ constraints is unsatisfiable with high probability when $m \gg n$. The natural algorithmic task in this regime is \emph{refutation}: finding a proof that…

Computational Complexity · Computer Science 2016-10-11 Ryuhei Mori , David Witmer

In this paper we introduce a new approach for approximately counting in bounded degree systems with higher-order constraints. Our main result is an algorithm to approximately count the number of solutions to a CNF formula $\Phi$ when the…

Data Structures and Algorithms · Computer Science 2017-03-17 Ankur Moitra

Consider a random $k$-CNF formula $F_{k}(n, rn)$ with $n$ variables and $rn$ clauses. For every truth assignment $\sigma\in \{0, 1\}^{n}$ and every clause $c=\ell_{1}\vee\cdots\vee\ell_{k}$, let $d=d(\sigma, c)$ be the number of satisfied…

Discrete Mathematics · Computer Science 2013-10-17 Zongsheng Gao , Jun Liu , Ke Xu

In this work we suggest a new model for generating random satisfiable k-CNF formulas. To generate such formulas -- randomly permute all 2^k\binom{n}{k} possible clauses over the variables x_1, ..., x_n, and starting from the empty formula,…

Combinatorics · Mathematics 2008-07-29 Michael Krivelevich , Benny Sudakov , Dan Vilenchik

We study random instances of the weighted $d$-CNF satisfiability problem (WEIGHTED $d$-SAT), a generic W[1]-complete problem. A random instance of the problem consists of a fixed parameter $k$ and a random $d$-CNF formula $\weicnf{n}{p}{k,…

Data Structures and Algorithms · Computer Science 2008-12-18 Yong Gao

We study the refutation complexity of graph isomorphism in the tree-like resolution calculus. Tor\'an and W\"orz (TOCL 2023) showed that there is a resolution refutation of narrow width $k$ for two graphs if and only if they can be…

Logic in Computer Science · Computer Science 2025-07-11 Christoph Berkholz , Moritz Lichter , Harry Vinall-Smeeth

Let $\Phi = (V, \mathcal{C})$ be a constraint satisfaction problem on variables $v_1,\dots, v_n$ such that each constraint depends on at most $k$ variables and such that each variable assumes values in an alphabet of size at most $[q]$.…

Data Structures and Algorithms · Computer Science 2020-11-25 Vishesh Jain , Huy Tuan Pham , Thuy Duong Vuong

The relationship between the complexity classes P and NP is an unsolved question in the field of theoretical computer science. In this paper, we investigate a descriptor approach based on lattice properties. This paper proposes a new way to…

Computational Complexity · Computer Science 2020-01-06 Marcel Rémon , Johan Barthélemy

We propose a new algorithmic framework, called "partial rejection sampling", to draw samples exactly from a product distribution, conditioned on none of a number of bad events occurring. Our framework builds (perhaps surprising) new…

Data Structures and Algorithms · Computer Science 2019-01-16 Heng Guo , Mark Jerrum , Jingcheng Liu

Open questions with respect to the computational complexity of linear CNF formulas in connection with regularity and uniformity are addressed. In particular it is proven that any l-regular monotone CNF formula is XSAT-unsatisfiable if its…

Computational Complexity · Computer Science 2018-01-19 Bernd. R. Schuh

For random CNF formulae with m clauses, n variables and an unrestricted number of literals per clause the transition from high to low satisfiability can be determined exactly for large n. The critical density m/n turns out to be strongly…

Computational Complexity · Computer Science 2012-04-10 Bernd R. Schuh

Two classical upper bounds on the Shannon capacity of graphs are the $\vartheta$-function due to Lov\'asz and the minrank parameter due to Haemers. We provide several explicit constructions of $n$-vertex graphs with a constant…

Data Structures and Algorithms · Computer Science 2018-02-22 Ishay Haviv

For typical first-order logical theories, satisfying assignments have a straightforward finite representation that can directly serve as a certificate that a given assignment satisfies the given formula. For non-linear real arithmetic…

Logic in Computer Science · Computer Science 2025-03-07 Enrico Lipparini , Stefan Ratschan