Like simpler graphs, nested (hypernodal) graphs consist of two components: a set of nodes and a set of edges, where each edge connects a pair of nodes. In the hypernodal graph model, however, a node may contain other graphs [1]; so that a node may be contained in a graph that it contains. The inherently recursive structure of the hypernodal graph model aptly characterizes both the structure and...

[1] We have analyzed the relationship between surface air temperature (SAT), ground surface temperature (GST), and snow cover (SNC) over the terrestrial Northern Hemisphere based on general circulation model (GCM) simulations using GISS modelE forced with the observed SST and radiative forcing changes from 1951–1998. While SAT is the dominant influence on GST during the warm-season, it explains...

In this paper, we introduce a new problem, called Top-k SAT, that consists in enumerating the Top-k models of a propositional formula. A Top-k model is defined as a model with less than k models preferred to it with respect to a preference relation. We show that Top-k SAT generalizes two well-known problems: the partial Max-SAT problem and the problem of computing minimal models. Moreover, we p...

In this paper we present a comparison of the SAT-based bounded model checking (BMC) and SMT-based bounded model checking methods for ECTL properties of a parallel composition of transition systems. In the both methods we use the parallel composition (of the transition systems) based on the interleaved semantics. Moreover, the both methods use the same bounded semantics of ECTL formulae, the com...

The large number of program variables in a software verification model often makes model checkers ineffective. Since the performance of BDD’s is very sensitive to the number of variables, BDD-based model checking is deficient in this regard. SAT-based model checking shows some promise because the performance of SAT-solvers is less dependent on the number of variables. As a result, SAT-based tec...

The satisfiability problem (SAT) is a well studied problem in logic which searches for a truth assignment of a set of Boolean variables that evaluates a specific formula to true. The bandwidth minimization problem for graphs (BMPG) is a well studied problem in graphs and requires finding the labels of the nodes of a graph such that the maximum absolute difference among neighbors is minimized. T...

SAT filters are a novel and compact data structure that can be used to quickly query a word for membership in a fixed set. They have the potential to store more information in a fixed storage limit than a Bloom filter. Constructing a SAT filter requires sampling diverse solutions to randomly constructed constraint satisfaction instances, but there is flexibility in the choice of constraint sati...

We describe LMHS, an open source weighted partial maximum satisfiability (MaxSAT) solver. LMHS is a hybrid SAT-IP MaxSAT solver that implements the implicit hitting set approach to MaxSAT. On top of the main algorithm, LMHS offers integrated preprocessing, solution enumeration, an incremental API, and the use of a choice of SAT and IP solvers. We describe the main features of LMHS, and give emp...

We investigate how SAT coaching (also known as “SAT Prep”) affects the value of the SAT as an evaluative tool, vis-á-vis other applicant signals such as high school transcript and letters of recommendation. Theoretically, we develop a simple “meritocratic” model of selective college admission that illustrates how SAT Prep may alter the emphasis a college places on SAT scores, depending on perce...

We consider a fully SAT-based method of unbounded symbolic model checking based on computing Craig interpolants. In benchmark studies using a set of large industrial circuit verification instances, this method is greatly more efficient than BDD-based symbolic model checking, and compares favorably to some recent SAT-based model checking methods on positive instances.