20 research outputs found
Lending Petri nets and contracts
Choreography-based approaches to service composition typically assume that,
after a set of services has been found which correctly play the roles
prescribed by the choreography, each service respects his role. Honest services
are not protected against adversaries. We propose a model for contracts based
on a extension of Petri nets, which allows services to protect themselves while
still realizing the choreography. We relate this model with Propositional
Contract Logic, by showing a translation of formulae into our Petri nets which
preserves the logical notion of agreement, and allows for compositional
verification
Contract agreements via logic
We relate two contract models: one based on event structures and game theory,
and the other one based on logic. In particular, we show that the notions of
agreement and winning strategies in the game-theoretic model are related to
that of provability in the logical model.Comment: In Proceedings ICE 2013, arXiv:1310.401
Debits and Credits in Petri Nets and Linear Logic
Exchanging resources often involves situations where a participant gives a resource without obtaining immediately the expected reward. For instance, one can buy an item without paying it in advance, but contracting a debt which must be eventually honoured. Resources, credits and debits can be represented, either implicitly or explicitly, in several formal models, among which Petri nets and linear logic. In this paper we study the relations between two of these models, namely intuitionistic linear logic with mix and Debit Petri nets. In particular, we establish a natural correspondence between provability in the logic, and marking reachability in nets
A Decidable Equivalence for a Turing-Complete, Distributed Model of Computation
Place/Transition Petri nets with inhibitor arcs (PTI nets for short), which are a well-known Turing-complete, distributed model of computation, are equipped with a decidable, behavioral equivalence, called pti-place bisimilarity, that conservatively extends place bisimilarity defined over Place/Transition nets (without inhibitor arcs). We prove that pti-place bisimilarity is sensible, as it respects the causal semantics of PTI nets
Vicious circles in contracts and in logic
Contracts are formal promises on the future interactions of participants, which describe the causal dependencies among their actions. An inherent feature of contracts is that such dependencies may be circular: for instance, a buyer promises to pay for an item if the seller promises to ship it, and vice versa. We establish a bridge between two formal models for contracts, one based on games over event structures, and the other one on Propositional Contract Logic. In particular, we show that winning strategies in the game-theoretic model correspond to proofs in the logi
A new operational representation of dependencies in Event Structures
The execution of an event in a complex and distributed system where the
dependencies vary during the evolution of the system can be represented in many
ways, and one of them is to use Context-Dependent Event structures. Event
structures are related to Petri nets. The aim of this paper is to propose what
can be the appropriate kind of Petri net corresponding to Context-Dependent
Event structures, giving an operational flavour to the dependencies represented
in a Context/Dependent Event structure. Dependencies are often operationally
represented, in Petri nets, by tokens produced by activities and consumed by
others. Here we shift the perspective using contextual arcs to characterize
what has happened so far and in this way to describe the dependencies among the
various activities