Title :
Bounds on thresholds related to maximum satisfiability of regular random formulas
Author :
Rathi, Vishwambhar ; Aurell, Erik ; Rasmussen, Lars ; Skoglund, Mikael
Author_Institution :
Sch. of Electr. Eng., KTH-R. Inst. of Technol., Stockholm, Sweden
Abstract :
We consider the regular balanced model of satisfiability formula generation in conjunctive normal form (CNF), where each literal participates in equal number of clauses and there are k literals participating in a clause. We say that a formula is p-satisfying if there is a truth assignment satisfying 1-2-k+p2-k fraction of clauses. Using the first moment method we determine upper bound on the threshold clause density such that there are no p-satisfying assignments with high probability above this upper bound. There are two aspects in deriving the lower bound using the second moment method. The first aspect is, given any p ∈ (0;1) and k, evaluate the lower bound on the threshold. This evaluation is numerical in nature. The second aspect is to derive the lower bound as a function of p for large enough k. We address the first aspect and evaluate the lower bound on the p-satisfying threshold using the second moment method. Based on the numerical evaluation, we observe that as k increases the ratio of the lower bound and the upper bound seems to converge to one.
Keywords :
computability; method of moments; probability; conjunctive normal form; maximum satisfiability; moment method; regular random formulas; truth assignment;
Conference_Titel :
Turbo Codes and Iterative Information Processing (ISTC), 2010 6th International Symposium on
Conference_Location :
Brest
Print_ISBN :
978-1-4244-6744-0
Electronic_ISBN :
978-1-4244-6745-7
DOI :
10.1109/ISTC.2010.5613816