scholarly journals Representing hybrid automata by action language modulo theories

2017 ◽  
Vol 17 (5-6) ◽  
pp. 924-941 ◽  
Author(s):  
JOOHYUNG LEE ◽  
NIKHIL LONEY ◽  
YUNSONG MENG
Keyword(s):  
Differential Equations ◽  
Ordinary Differential Equations ◽  
Satisfiability Modulo Theories ◽  
Prototype System ◽  
Hybrid Automata ◽  
Action Languages ◽  
Smt Solver ◽  
Action Language ◽  
Linear Hybrid Automata ◽  
Answer Set

AbstractBoth hybrid automata and action languages are formalisms for describing the evolution of dynamic systems. This paper establishes a formal relationship between them. We show how to succinctly represent hybrid automata in an action language which in turn is defined as a high-level notation for answer set programming modulo theories—an extension of answer set programs to the first-order level similar to the way satisfiability modulo theories (SMT) extends propositional satisfiability (SAT). We first show how to represent linear hybrid automata with convex invariants by an action language modulo theories. A further translation into SMT allows for computing them using SMT solvers that support arithmetic over reals. Next, we extend the representation to the general class of non-linear hybrid automata allowing even non-convex invariants. We represent them by an action language modulo ordinary differential equations, which can be compiled into satisfiability modulo ordinary differential equations. We present a prototype systemcplus2aspmtbased on these translations, which allows for a succinct representation of hybrid transition systems that can be computed effectively by the state-of-the-art SMT solverdReal.

Action language ℬ𝒞+

2015 ◽  
Vol 30 (4) ◽  
pp. 899-922 ◽  
Author(s):  
Joseph Babb ◽  
Joohyung Lee
Keyword(s):  
Main Idea ◽  
Answer Set Programming ◽  
Stable Model ◽  
Formal Models ◽  
Transition Systems ◽  
Action Languages ◽  
Action Language ◽  
Language Constructs ◽  
High Level ◽  
Answer Set

Abstract Action languages are formal models of parts of natural language that are designed to describe effects of actions. Many of these languages can be viewed as high-level notations of answer set programs structured to represent transition systems. However, the form of answer set programs considered in the earlier work is quite limited in comparison with the modern Answer Set Programming (ASP) language, which allows several useful constructs for knowledge representation, such as choice rules, aggregates and abstract constraint atoms. We propose a new action language called BC +, which closes the gap between action languages and the modern ASP language. The main idea is to define the semantics of BC + in terms of general stable model semantics for propositional formulas, under which many modern ASP language constructs can be identified with shorthands for propositional formulas. Language BC  + turns out to be sufficiently expressive to encompass the best features of other action languages, such as languages B , C , C + and BC . Computational methods available in ASP solvers are readily applicable to compute BC +, which led to an implementation of the language by extending system cplus2asp .

scholarly journals Fuzzy answer set computation via satisfiability modulo theories

2015 ◽  
Vol 15 (4-5) ◽  
pp. 588-603 ◽  
Author(s):  
MARIO ALVIANO ◽  
RAFAEL PEÑALOZA
Keyword(s):  
Fuzzy Logic ◽  
Structural Properties ◽  
Answer Set Programming ◽  
Satisfiability Modulo Theories ◽  
Prototype System ◽  
Imprecise Information ◽  
Fuzzy Connectives ◽  
Answer Set

AbstractFuzzy answer set programming (FASP) combines two declarative frameworks, answer set programming and fuzzy logic, in order to model reasoning by default over imprecise information. Several connectives are available to combine different expressions; in particular the Gödel and Łukasiewicz fuzzy connectives are usually considered, due to their properties. Although the Gödel conjunction can be easily eliminated from rule heads, we show through complexity arguments that such a simplification is infeasible in general for all other connectives. The paper analyzes a translation of FASP programs into satisfiability modulo theories (SMT), which in general produces quantified formulas because of the minimality of the semantics. Structural properties of many FASP programs allow to eliminate the quantification, or to sensibly reduce the number of quantified variables. Indeed, integrality constraints can replace recursive rules commonly used to force Boolean interpretations, and completion subformulas can guarantee minimality for acyclic programs with atomic heads. Moreover, head cycle free rules can be replaced by shifted subprograms, whose structure depends on the eliminated head connective, so that ordered completion may replace the minimality check if also Łukasiewicz disjunction in rule bodies is acyclic. The paper also presents and evaluates a prototype system implementing these translations.

scholarly journals SMT Encoding of Hybrid Systems in dReal

10.29007/s3b9 ◽  
2018 ◽  
Author(s):  
Kyungmin Bae ◽  
Soonho Kong ◽  
Sicun Gao
Keyword(s):  
Model Checking ◽  
Differential Equations ◽  
Ordinary Differential Equations ◽  
Hybrid Systems ◽  
Bounded Model Checking ◽  
Satisfiability Modulo Theories ◽  
Real Numbers ◽  
The Real ◽  
Real Functions ◽  
Nonlinear Hybrid

Analysis problems of hybrid systems, involving nonlinear real functions and ordinary differential equations, can be reduced to SMT (satisfiability modulo theories) problems over the real numbers. The dReal solver can automatically check the satisfiability of such SMT formulas up to a given precision δ > 0. This paper explains how bounded model checking problems of hybrid systems are encoded in dReal. In particular, a novel SMT syntax of dReal enables to effectively represent networks of hybrid systems in a modular way. We illustrate SMT encoding in dReal with simple nonlinear hybrid systems.

Engineering Theories with Z3

10.29007/x7b4 ◽  
2018 ◽  
Author(s):  
Nikolaj Bjorner
Keyword(s):  
Satisfiability Modulo Theories ◽  
Smt Solver ◽  
Testing Tools ◽  
Software And Hardware ◽  
Design And Testing

Modern Satisfiability Modulo Theories (SMT)solvers are fundamental to many programanalysis, verification, design and testing tools. They are a goodfit for the domain of software and hardware engineering becausethey support many domains that are commonly used by the tools.The meaning of domains are captured by theories that can beaxiomatized or supported by efficient <i>theory solvers</i>.Nevertheless, not all domains are handled by all solvers andmany domains and theories will never be native to any solver.We here explore different theories that extend MicrosoftResearch's SMT solver Z3's basicsupport. Some can be directly encoded or axiomatized,others make use of user theory plug-ins.Plug-ins are a powerful way for tools to supply their custom domains.

Sign in / Sign up

Export Citation Format

Share Document