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- Jaco Geldenhuys, Henri Hansen
- SPIN
- 2006

Many different automata and algorithms have been investigated in the context of automata-theoretic LTL model checking. This article compares the behaviour of two variations on the widely used Büchi automaton, namely (i) a Büchi automaton where states are labelled with atomic propositions and transitions are unlabelled, and (ii) a form of testing automaton… (More)

- Antti Valmari, Henri Hansen
- Fundam. Inform.
- 2010

Literature on the stubborn set and similar state space reduction methods presents numerous seemingly ad-hoc conditions for selecting the transitions that are investigated in the current state. There are good reasons to believe that the choice between them has a significant effect on reduction results, but not much has been published on this topic. This… (More)

- Henri Hansen, Wojciech Penczek, Antti Valmari
- Electr. Notes Theor. Comput. Sci.
- 2002

The research examines liveness and progress properties of concurrent systems and their on-the-fly verification. An alternative formalism to Büchi automata, called testing automata, is developed. The basic idea of testing automata is to observe changes in the values of state propositions instead of the values. Therefore, the testing automata are able to… (More)

- Antti Valmari, Henri Hansen
- Fundam. Inform.
- 2012

Many algorithms for computing minimal coverability sets for Petri nets prune futures. That is, if a new marking strictly covers an old one, then not just the old marking but also some subset of its successor markings is discarded from search. In this publication, a simpler algorithm that lacks future pruning is presented and proven correct. Its performance… (More)

- Henri Hansen, Heikki Virtanen, Antti Valmari
- ACSD
- 2003

A formalism is presented that is intended to combine basic properties of both state-based and action-based verification. In state-based verification the behaviour of the system is described in terms of the properties of its states, whereas action-based methods concentrate on transitions between states. A typical state-based approach consists of representing… (More)

- Jaco Geldenhuys, Henri Hansen, Antti Valmari
- ATVA
- 2009

Partial order reduction methods combat state explosion by exploring only a part of the full state space. In each state a subset of enabled transitions is selected using well-established criteria. Typically such criteria are based on an upper approximation of dependencies between transitions. An additional heuristic is needed to ensure that currently… (More)

- Henri Hansen, Marta Z. Kwiatkowska, Hongyang Qu
- QEST
- 2011

—Fairness assumptions are needed to verify liveness properties of concurrent systems. In this paper we explore the so-called unconditional fairness in Markov decision processes (MDPs), which is a prerequisite for quantitative assume-guarantee reasoning. Unconditional fairness refers to executions where all processes are guaranteed to participate. We prove… (More)

- Heikki Virtanen, Henri Hansen, Antti Valmari, Juha Nieminen, Timo Erkkilä
- TACAS
- 2004

Tampere Verification Tool (TVT) is a collection of programs for automated verification of concurrent and reactive systems. TVT has its roots in process algebras and explicit state space exploration, but in addition to actions, our formalism allows use of state-based information in the form of truth-valued state propositions. Furthermore, it contains three… (More)

- Henri Hansen, Xu Wang
- Petri Nets
- 2011

In prime event structures with binary conflicts (pes-bc) 3 a branching cell [1] is a subset of events closed under downward causality and immediate conflict relations. This means that no event outside the branching cell can be in conflict with or enable any event inside the branching cell. It bears a strong resemblance to stubborn sets, a partial order… (More)

- Henri Hansen, Shang-Wei Lin, Yang Liu, Truong Khanh Nguyen, Jun Sun
- CAV
- 2014

A major obstacle for using partial order reduction in the context of real time verification is that the presence of clocks and clock constraints breaks the usual diamond structure of otherwise independent transitions. This is especially true when information of the relative values of clocks is preserved in the form of diagonal constraints. However, when… (More)