On convergence-sensitive bisimulation and the embedding of CCS in timed CCS

We propose a notion of convergence-sensitive bisimulation that is built just over the notions of (internal) reduction and of (static) context. In the framework of timed CCS, we characterise this notion of `contextual' bisimulation via the usual labelled transition system. We also remark that it provides a suitable semantic framework for a fully abstract embedding of untimed processes into timed ones. Finally, we show that the notion can be refined to include sensitivity to divergence

Appetite for destruction. Current interpretations of accidental or deliberate destructions in Bronze Age Cyprus

Destruction processes are considered 'time capsules of material culture' (Driessen 2013) as they freeze a site at one moment of its history providing key evidence for interpreting the archaeological record and reconstructing social, political, cultural and ideological circumstances. By focusing on selected case-studies, this paper aims at briefly discussing existing evidence of destruction events in Bronze Age contexts in Cyprus, and at a preliminary presentation of new research data resulting from ongoing interdisciplinary analyses at Middle Bronze Age Erimi

On the Decidability of Fragments of the Asynchronous Pi-Calculus

We study the decidability of a reachability problem for various fragments of the asynchronous $\pi$-calculus. We consider the combination of three main features: name generation, name mobility, and unbounded control. We show that the combination of name generation with either name mobility or unbounded control leads to an undecidable fragment. On the other hand, we prove that name generation without name mobility and with bounded control is decidable by reduction to the coverability problem for Petri Nets

An Elementary affine λ-calculus with multithreading and side effects (extended version)

Linear logic provides a framework to control the complexity of higher-order functional programs. We present an extension of this framework to programs with multithreading and side effects focusing on the case of elementary time. Our main contributions are as follows. First, we provide a new combinatorial proof of termination in elementary time for the functional case. Second, we develop an extension of the approach to a call-by-value $lambda$-calculus with multithreading and side effects. Third, we introduce an elementary affine type system that guarantees the standard subject reduction and progress properties. Finally, we illustrate the programming of iterative functions with side effects in the presented formalism

On the decidability of fragments of the asynchronous π-calculus

AbstractWe study the decidability of a reachability problem for various fragments of the asynchronous π-calculus. We consider the combination of three main features: name generation, name mobility, and unbounded control. We show that the combination of name generation with either name mobility or unbounded control leads to an undecidable fragment. On the other hand, we prove that name generation without name mobility and with bounded control is decidable by reduction to the coverability problem for Petri Nets

Certifying and reasoning about cost annotations of functional programs

We present a so-called labelling method to insert cost annotations in a higher-order functional program, to certify their correctness with respect to a standard compilation chain to assembly code including safe memory management, and to reason on them in a higher-order Hoare logic.Comment: Higher-Order and Symbolic Computation (2013

The Receptive Distributed π\pi-Calculus

In this paper we study an asynchronous distributed $\pi$-calculus, with constructs for localities and migration. We show that a simple static analysis ensures the receptiveness of channel names, which, together with a simple type system, guarantees a local deadlock-freedom property, that we call message deliverability. This property states that any migrating message will find an appropriate receiver at its destination locality. We argue that this distributed, receptive calculus is still expressive enough, by giving a series of examples illustrating the «receptive style» of programming we have. Finally we show that our calculus contains the $\pi_1$-calculus, up to weak asynchronous bisimulation

On bisimulations for the asynchronous π-calculus

AbstractThe asynchronous π-calculus is a variant of the π-calculus where message emission is non-blocking. Honda and Tokoro have studied a semantics for this calculus based on bisimulation. Their bisimulation relies on a modified transition system where, at any moment, a process can perform any input action.In this paper we propose a new notion of bisimulation for the asynchronous π-calculus, defined on top of the standard labelled transition system. We give several characterizations of this equivalence including one in terms of Honda and Tokoro's bisimulation, and one in terms of barbed equivalence. We show that this bisimulation is preserved by name substitutions, hence by input prefix. Finally, we give a complete axiomatization of the (strong) bisimulation for finite terms