Title
Faster extraction of high-level minimal unsatisfiable cores
Abstract
Various verification techniques are based on SAT's capability to identify a small, or even minimal, unsatisfiable core in case the formula is unsatisfiable, i.e., a small subset of the clauses that are unsatisfiable regardless of the rest of the formula. In most cases it is not the core itself that is being used, rather it is processed further in order to check which clauses from a preknown set of Interesting Constraints (where each constraint is modeled with a conjunction of clauses) participate in the proof. The problem of minimizing the participation of interesting constraints was recently coined high-level minimal unsatisfiable core by Nadel [15]. Two prominent examples of verification techniques that need such small cores are 1) abstraction-refinement model-checking techniques, which use the core in order to identify the state variables that will be used for refinement (smaller number of such variables in the core implies that more state variables can be replaced with free inputs in the abstract model), and 2) assumption minimization, where the goal is to minimize the usage of environment assumptions in the proof, because these assumptions have to be proved separately. We propose seven improvements to the recent solution given in [15], which together result in an overall reduction of 55% in run time and 73% in the size of the resulting core, based on our experiments with hundreds of industrial test cases. The optimized procedure is also better empirically than the assumptions-based minimization technique.
Year
DOI
Venue
2011
10.1007/978-3-642-21581-0_15
SAT
Keywords
Field
DocType
various verification technique,unsatisfiable core,resulting core,state variable,faster extraction,assumptions-based minimization technique,assumption minimization,small subset,high-level minimal unsatisfiable core,small core,verification technique
Discrete mathematics,Combinatorics,Model checking,Decision level,Computer science,Unsatisfiable core,Algorithm,Minification,State variable,Test case
Conference
Volume
ISSN
Citations 
6695
0302-9743
27
PageRank 
References 
Authors
1.01
22
2
Name
Order
Citations
PageRank
Vadim Ryvchin1755.68
Ofer Strichman2107163.61