24 research outputs found
Parameterized verification
The goal of parameterized verification is to prove the correctness of a system specification regardless of the number of its components. The problem is of interest in several different areas: verification of hardware design, multithreaded programs, distributed systems, and communication protocols. The problem is undecidable in general. Solutions for restricted classes of systems and properties have been studied in areas like theorem proving, model checking, automata and logic, process algebra, and constraint solving. In this introduction to the special issue, dedicated to a selection of works from the Parameterized Verification workshop PV \u201914 and PV \u201915, we survey some of the works developed in this research area
Forward Analysis and Model Checking for Trace Bounded WSTS
We investigate a subclass of well-structured transition systems (WSTS), the
bounded---in the sense of Ginsburg and Spanier (Trans. AMS 1964)---complete
deterministic ones, which we claim provide an adequate basis for the study of
forward analyses as developed by Finkel and Goubault-Larrecq (Logic. Meth.
Comput. Sci. 2012). Indeed, we prove that, unlike other conditions considered
previously for the termination of forward analysis, boundedness is decidable.
Boundedness turns out to be a valuable restriction for WSTS verification, as we
show that it further allows to decide all -regular properties on the
set of infinite traces of the system
A unified view of parameterized verification of abstract models of broadcast communication
We give a unified view of different parameterized models of concurrent and distributed systems with broadcast communication based on transition systems. Based on the resulting formal models, we discuss related verification methods and tools based on abstractions and symbolic state exploration
Coverability Trees for Petri Nets with Unordered Data
We study an extension of classical Petri nets where tokens carry values from a countable data domain, that can be tested for equality upon firing transitions. These Unordered Data Petri Nets (UDPN) are well-structured and therefore allow generic decision procedures for several verification problems including coverability and boundedness. We show how to construct a finite representation of the coverability set in terms of its ideal decomposition. This not only provides an alternative method to decide coverability and boundedness, but is also an important step towards deciding the reachability problem. This also allows to answer more precise questions about the reachability set, for instance whether there is a bound on the number of tokens on a given place (place boundedness), or if such a bound exists for the number of different data values carried by tokens (place width boundedness). We provide matching Hyper-Ackermann bounds on the size of cover-ability trees and on the running time of the induced decision procedures
Model Checking Linear Logic Specifications
The overall goal of this paper is to investigate the theoretical foundations
of algorithmic verification techniques for first order linear logic
specifications. The fragment of linear logic we consider in this paper is based
on the linear logic programming language called LO enriched with universally
quantified goal formulas. Although LO was originally introduced as a
theoretical foundation for extensions of logic programming languages, it can
also be viewed as a very general language to specify a wide range of
infinite-state concurrent systems.
Our approach is based on the relation between backward reachability and
provability highlighted in our previous work on propositional LO programs.
Following this line of research, we define here a general framework for the
bottom-up evaluation of first order linear logic specifications. The evaluation
procedure is based on an effective fixpoint operator working on a symbolic
representation of infinite collections of first order linear logic formulas.
The theory of well quasi-orderings can be used to provide sufficient conditions
for the termination of the evaluation of non trivial fragments of first order
linear logic.Comment: 53 pages, 12 figures "Under consideration for publication in Theory
and Practice of Logic Programming
IST Austria Thesis
Motivated by the analysis of highly dynamic message-passing systems, i.e. unbounded thread creation, mobility, etc. we present a framework for the analysis of depth-bounded systems. Depth-bounded systems are one of the most expressive known fragment of the Ï-calculus for which interesting verification problems are still decidable. Even though they are infinite state systems depth-bounded systems are well-structured, thus can be analyzed algorithmically. We give an interpretation of depth-bounded systems as graph-rewriting systems. This gives more flexibility and ease of use to apply depth-bounded systems to other type of systems like shared memory concurrency.
First, we develop an adequate domain of limits for depth-bounded systems, a prerequisite for the effective representation of downward-closed sets. Downward-closed sets are needed by forward saturation-based algorithms to represent potentially infinite sets of states. Then, we present an abstract interpretation framework to compute the covering set of well-structured transition systems. Because, in general, the covering set is not computable, our abstraction over-approximates the actual covering set. Our abstraction captures the essence of acceleration based-algorithms while giving up enough precision to ensure convergence. We have implemented the analysis in the PICASSO tool and show that it is accurate in practice. Finally, we build some further analyses like termination using the covering set as starting point
Affine Extensions of Integer Vector Addition Systems with States
We study the reachability problem for affine -VASS, which are
integer vector addition systems with states in which transitions perform affine
transformations on the counters. This problem is easily seen to be undecidable
in general, and we therefore restrict ourselves to affine -VASS
with the finite-monoid property (afmp--VASS). The latter have the
property that the monoid generated by the matrices appearing in their affine
transformations is finite. The class of afmp--VASS encompasses
classical operations of counter machines such as resets, permutations,
transfers and copies. We show that reachability in an afmp--VASS
reduces to reachability in a -VASS whose control-states grow
linearly in the size of the matrix monoid. Our construction shows that
reachability relations of afmp--VASS are semilinear, and in
particular enables us to show that reachability in -VASS with
transfers and -VASS with copies is PSPACE-complete. We then focus
on the reachability problem for affine -VASS with monogenic
monoids: (possibly infinite) matrix monoids generated by a single matrix. We
show that, in a particular case, the reachability problem is decidable for this
class, disproving a conjecture about affine -VASS with infinite
matrix monoids we raised in a preliminary version of this paper. We complement
this result by presenting an affine -VASS with monogenic matrix
monoid and undecidable reachability relation