17 research outputs found
Equivalence-Checking on Infinite-State Systems: Techniques and Results
The paper presents a selection of recently developed and/or used techniques
for equivalence-checking on infinite-state systems, and an up-to-date overview
of existing results (as of September 2004)
Tools and Algorithms for the Construction and Analysis of Systems
This open access two-volume set constitutes the proceedings of the 27th International Conference on Tools and Algorithms for the Construction and Analysis of Systems, TACAS 2021, which was held during March 27 – April 1, 2021, as part of the European Joint Conferences on Theory and Practice of Software, ETAPS 2021. The conference was planned to take place in Luxembourg and changed to an online format due to the COVID-19 pandemic. The total of 41 full papers presented in the proceedings was carefully reviewed and selected from 141 submissions. The volume also contains 7 tool papers; 6 Tool Demo papers, 9 SV-Comp Competition Papers. The papers are organized in topical sections as follows: Part I: Game Theory; SMT Verification; Probabilities; Timed Systems; Neural Networks; Analysis of Network Communication. Part II: Verification Techniques (not SMT); Case Studies; Proof Generation/Validation; Tool Papers; Tool Demo Papers; SV-Comp Tool Competition Papers
Model checking infinite-state systems: generic and specific approaches
Model checking is a fully-automatic formal verification method that has been extremely
successful in validating and verifying safety-critical systems in the past three
decades. In the past fifteen years, there has been a lot of work in extending many
model checking algorithms over finite-state systems to finitely representable infinitestate
systems. Unlike in the case of finite systems, decidability can easily become a
problem in the case of infinite-state model checking.
In this thesis, we present generic and specific techniques that can be used to derive
decidability with near-optimal computational complexity for various model checking
problems over infinite-state systems. Generic techniques and specific techniques primarily
differ in the way in which a decidability result is derived. Generic techniques is
a “top-down” approach wherein we start with a Turing-powerful formalismfor infinitestate
systems (in the sense of being able to generate the computation graphs of Turing
machines up to isomorphisms), and then impose semantic restrictions whereby the
desired model checking problem becomes decidable. In other words, to show that a
subclass of the infinite-state systems that is generated by this formalism is decidable
with respect to the model checking problem under consideration, we will simply have
to prove that this subclass satisfies the semantic restriction. On the other hand, specific
techniques is a “bottom-up” approach in the sense that we restrict to a non-Turing
powerful formalism of infinite-state systems at the outset. The main benefit of generic
techniques is that they can be used as algorithmic metatheorems, i.e., they can give
unified proofs of decidability of various model checking problems over infinite-state
systems. Specific techniques are more flexible in the sense they can be used to derive
decidability or optimal complexity when generic techniques fail.
In the first part of the thesis, we adopt word/tree automatic transition systems as
a generic formalism of infinite-state systems. Such formalisms can be used to generate
many interesting classes of infinite-state systems that have been considered in the
literature, e.g., the computation graphs of counter systems, Turing machines, pushdown
systems, prefix-recognizable systems, regular ground-tree rewrite systems, PAprocesses,
order-2 collapsible pushdown systems. Although the generality of these
formalisms make most interesting model checking problems (even safety) undecidable,
they are known to have nice closure and algorithmic properties. We use these
nice properties to obtain several algorithmic metatheorems over word/tree automatic
systems, e.g., for deriving decidability of various model checking problems including
recurrent reachability, and Linear Temporal Logic (LTL) with complex fairness constraints. These algorithmic metatheorems can be used to uniformly prove decidability
with optimal (or near-optimal) complexity of various model checking problems over
many classes of infinite-state systems that have been considered in the literature. In
fact, many of these decidability/complexity results were not previously known in the
literature.
In the second part of the thesis, we study various model checking problems over
subclasses of counter systems that were already known to be decidable. In particular,
we consider reversal-bounded counter systems (and their extensions with discrete
clocks), one-counter processes, and networks of one-counter processes. We shall derive
optimal complexity of various model checking problems including: model checking
LTL, EF-logic, and first-order logic with reachability relations (and restrictions
thereof). In most cases, we obtain a single/double exponential reduction in the previously
known upper bounds on the complexity of the problems
Computer Aided Verification
This open access two-volume set LNCS 10980 and 10981 constitutes the refereed proceedings of the 30th International Conference on Computer Aided Verification, CAV 2018, held in Oxford, UK, in July 2018. The 52 full and 13 tool papers presented together with 3 invited papers and 2 tutorials were carefully reviewed and selected from 215 submissions. The papers cover a wide range of topics and techniques, from algorithmic and logical foundations of verification to practical applications in distributed, networked, cyber-physical, and autonomous systems. They are organized in topical sections on model checking, program analysis using polyhedra, synthesis, learning, runtime verification, hybrid and timed systems, tools, probabilistic systems, static analysis, theory and security, SAT, SMT and decisions procedures, concurrency, and CPS, hardware, industrial applications
Computer Aided Verification
This open access two-volume set LNCS 10980 and 10981 constitutes the refereed proceedings of the 30th International Conference on Computer Aided Verification, CAV 2018, held in Oxford, UK, in July 2018. The 52 full and 13 tool papers presented together with 3 invited papers and 2 tutorials were carefully reviewed and selected from 215 submissions. The papers cover a wide range of topics and techniques, from algorithmic and logical foundations of verification to practical applications in distributed, networked, cyber-physical, and autonomous systems. They are organized in topical sections on model checking, program analysis using polyhedra, synthesis, learning, runtime verification, hybrid and timed systems, tools, probabilistic systems, static analysis, theory and security, SAT, SMT and decisions procedures, concurrency, and CPS, hardware, industrial applications