Program specialisation aims at improving the overall performance of programs by performing source to source transformations. A common approach within functional and logic programming, known respectively as partial evaluation and partial deduction, is to exploit partial knowledge about the input. It is achieved through a well-automated application of parts of the Burstall-Darlington unfold/fold transformation framework. The main challenge in developing systems is to design automatic control that ensures correctness, efficiency, and termination. This survey and tutorial presents the main developments in controlling partial deduction over the past 10 years and analyses their respective merits and shortcomings. It ends with an assessment of current achievements and sketches some remaining research challenges.

In recent work it has been shown that infinite state model checking can be performed by a combination of partial deduction of logic programs and abstract interpretation. This paper focuses on a particular class of problems - coverability for (infinite state) Petri nets| - and shows how existing techniques and tools for declarative programs can be successfully applied. In particular, we show that a restricted form of partial deduction is already powerful enough to decide all coverability properties of Petri Nets. We also prove that two particular instances of partial deduction exactly compute the Karp-Miller tree as well as Finkel's minimal coverability set. We thus establish a link between algorithms for Petri nets and logic program specialisation.

Abstract. Well-quasi orders in general, and homeomorphic embedding in particular, have gained popularity to ensure the termination of techniques for program analysis, specialisation, transformation, and verification. In this paper we survey and discuss this use of homeomorphic embedding and clarify the advantages of such an approach over one using well-founded orders. We also discuss various extensions of the homeomorphic embedding relation. We conclude with a study of homeomorphic embedding in the context of metaprogramming, presenting some new (positive and negative) results and open problems.

Abstract. The semantics of the OR-join in business process modeling languages like EPCs or YAWL have been discussed for a while. Still, the existing solutions suffer from at least one of two major problems. First, several formalizations depend upon restrictions of the EPC to a subset. Second, several approaches contradict the modeling intuition since the structuredness of the process does not guarantee soundness. In this paper, we present a novel semantical definition of EPCs that addresses these aspects yielding a formalization that is applicable for all EPCs and for which structuredness is a sufficient condition for soundness. Furthermore, we introduce a set of reduction rules for the verification of an EPC-specific soundness criterion and present a respective implementation. 1

Abstract. We present an abstract partial deduction technique which uses regular types as its domain and which can handle conjunctions, and thus perform deforestation and tupling. We provide a detailed description of all the required operations and present an implementation within the ecce system. We discuss the power of this new specialisation algorithm, especially in the light of verifying and specialising infinite state process algebras. Here, our new algorithm can provide a more precise treatment of synchronisation and can be used for refinement checking. 1

Abstract. When dealing with complex business processes (e.g., in the context of a workflow implementation or the configuration of some process-aware information system), it is important but sometimes difficult to determine whether a process contains any errors. The concepts such as cancellation and OR-joins occur naturally in business scenarios but the presence of these features in process models poses new challenges for verification. We take on the challenge of finding new verification techniques for workflows with cancellation regions and OR-joins. The proposed approach relies on reset nets and reachability analysis. We present these techniques in the context of workflow language YAWL that provides direct support for these features. We have extended the graphical editor of YAWL with these diagnostic features. Keywords: Workflow verification, Cancellation, OR-joins, Reset nets, YAWL. 1

Abstract. In earlier work it has been shown that finite state CTL model checking of reactive systems can be achieved by a relatively simple interpreter written in tabled logic programming. This approach is flexible in the sense that various specification formalisms can be easily targeted (e.g., Petri nets, CSP,...). Moreover, infinite state CTL model checking can be performed by analysing this interpreter using a combination of partial deduction and abstract interpretation. It has also been shown that this approach is powerful enough to decide coverability properties of various kinds of Petri nets. In this ongoing work, we are empirically evaluating these approaches on various case studies of finite, parameterised and infinite systems. For finite state systems, we show how our approach and tool compares to standard tools for finite state model checking For parameterised or infinite state model checking, we are comparing our results with, e.g., XMC, Hytech. 1

Generating inductive verification proofs for Isabelle using

Abstract. In this paper we discuss the similarities between program specialisation and inductive theorem proving, and then show how program specialisation can be used to perform inductive theorem proving. We then study this relationship in more detail for the particular problem of verifying infinite state systems in order to establish a clear link between program specialisation and inductive theorem proving. Indeed, Ecce is a program specialisation system which can be used to automatically generate abstractions for the model checking of infinite state systems. We show that to verify the abstractions generated by Ecce we may employ the proof assistant Isabelle. Thereby Ecce is used to generate the specification, hypotheses and proof script in Isabelle’s theory format. Then, in many cases, Isabelle can automatically execute these proof scripts and thereby verify the soundness of Ecce’s abstraction. In this work we focus on the specification and verification of Petri nets. 1

. We develop an abstract partial deduction method capable of