Title
Schaefer's theorem for graphs
Abstract
Schaefer's theorem is a complexity classification result for so-called Boolean constraint satisfaction problems: it states that every Boolean constraint satisfaction problem is either contained in one out of six classes and can be solved in polynomial time, or is NP-complete. We present an analog of this dichotomy result for the propositional logic of graphs instead of Boolean logic. In this generalization of Schaefer's result, the input consists of a set W of variables and a conjunction Phi of statements ("constraints") about these variables in the language of graphs, where each statement is taken from a fixed finite set Psi of allowed quantifier-free first-order formulas; the question is whether Phi is satisfiable in a graph. We prove that either Psi is contained in one out of 17 classes of graph formulas and the corresponding problem can be solved in polynomial time, or the problem is NP-complete. This is achieved by a universal-algebraic approach, which in turn allows us to use structural Ramsey theory. To apply the universal-algebraic approach, we formulate the computational problems under consideration as constraint satisfaction problems (CSPs) whose templates are first-order definable in the countably infinite random graph. Our method to classify the computational complexity of those CSPs produces many statements of independent mathematical interest.
Year
DOI
Venue
2011
10.1145/2764899
Clinical Orthopaedics and Related Research
Keywords
DocType
Volume
dichotomy result,corresponding problem,computational problem,boolean logic,boolean constraint satisfaction problem,constraint satisfaction problem,polynomial time,complexity classification result,countably infinite random graph,universal-algebraic approach,propositional logic,satisfiability,constraint satisfaction problems,random graph,universal algebra,polymorphism,correspondence problem,first order,computational complexity,ramsey theory
Conference
62
Issue
ISSN
Citations 
3
0004-5411
14
PageRank 
References 
Authors
0.83
23
2
Name
Order
Citations
PageRank
Manuel Bodirsky164454.63
Michael Pinsker213217.54