Le città dei vivi e dei morti. L’archeologia (ri)costruisce il nostro passato

Chi, di fronte a una mostra dal titolo La forza delle rovine, immaginasse di visitare la consueta esposizione di bucolici paesaggi pittorici disseminati di colonne spezzate e architetture classiche avvolte da rampicanti, rimarrebbe deluso. Sebbene una sezione sia dedicata ai paesaggi con rovine antiche nella pittura a partire dal XVI secolo fino al XX, questo tema non è stato mai centrale nella concezione della mostra, almeno per due motivi: il primo è che pur degno di interesse, il soggetto è altresì di scarsa originalità; l’altro è insito nella stessa idea generatrice di trattare le rovine come un fenomeno culturale più esteso possibile, che sollecitasse il visitatore al pensiero piuttosto che blandirlo con una anòdina esposizione di opere d’arte

Loosening the notions of compliance and sub-behaviour in client/server systems

In the context of "session behaviors" for client/server systems, we propose a weakening of the compliance and sub-behaviour relations where the bias toward the client (whose "requests" must be satisfied) is pushed further with respect to the usual definitions, by admitting that "not needed" output actions from the server side can be "skipped" by the client. Both compliance and sub-behaviour relations resulting from this weakening remain decidable, though the proof of the duals-as-minima property for servers, on which the decidability of the sub-behaviour relation relies, requires a tighter analysis of client/server interactions.Comment: In Proceedings ICE 2014, arXiv:1410.701

Orchestrated Session Compliance

We investigate the notion of orchestrated compliance for client/server interactions in the context of session contracts. Devising the notion of orchestrator in such a context makes it possible to have orchestrators with unbounded buffering capabilities and at the same time to guarantee any message from the client to be eventually delivered by the orchestrator to the server, while preventing the server from sending messages which are kept indefinitely inside the orchestrator. The compliance relation is shown to be decidable by means of 1) a procedure synthesising the orchestrators, if any, making a client compliant with a server, and 2) a procedure for deciding whether an orchestrator behaves in a proper way as mentioned before.Comment: In Proceedings ICE 2015, arXiv:1508.0459

Characterisation of Strongly Normalising lambda-mu-Terms

We provide a characterisation of strongly normalising terms of the lambda-mu-calculus by means of a type system that uses intersection and product types. The presence of the latter and a restricted use of the type omega enable us to represent the particular notion of continuation used in the literature for the definition of semantics for the lambda-mu-calculus. This makes it possible to lift the well-known characterisation property for strongly-normalising lambda-terms - that uses intersection types - to the lambda-mu-calculus. From this result an alternative proof of strong normalisation for terms typeable in Parigot's propositional logical system follows, by means of an interpretation of that system into ours.Comment: In Proceedings ITRS 2012, arXiv:1307.784

A Type Inference Algorithm for Secure Ambients

We consider a type discipline for the Ambient Calculus that associates ambients with security levels and constrains them to be traversed by or opened in ambients of higher security clearance only. We present a bottom-up algorithm that, given an untyped process $P$, computes a minimal set of constraints on security levels such that all actions during runs of $P$ are performed without violating the security level priorities. Such an algorithm appears to be a prerequisite to use type systems to ensure security properties in the web scenario

Space-Aware Ambients and Processes

Resource control has attracted increasing interest in foundational research on distributed systems. This paper focuses on space control and develops an analysis of space usage in the context of an ambient-like calculus with bounded capacities and weighed processes, where migration and activation require space. A type system complements the dynamics of the calculus by providing static guarantees that the intended capacity bounds are preserved throughout the computation

The Envy of Daedalus. Essay on the Artist as Murderer

Why the myth of Daedalus, the protos euretes, is connected with envy and murder? The author takes as his starting point Ovid’s Metamorphoses, where Daedalus’ envy drives him to murder his pupil and nephew Perdix. He also considers the passage of Seneca the Elder, about the painter Parrhasius and the citizen from Olynthus, that he had tortured in order to paint the agony of Prometheus. The first case is a topos of the artist’s biography which im- plies, that the craft of the artisan was held as a guarded secret; the second is related to mimesis. The author questions what role the topos of the artist as murderer plays in text and imagery, from the Middle Ages to modern literature

Retractable Contracts

In calculi for modelling communication protocols, internal and external choices play dual roles. Two external choices can be viewed naturally as dual too, as they represent an agreement between the communicating parties. If the interaction fails, the past agreements are good candidates as points where to roll back, in order to take a different agreement. We propose a variant of contracts with synchronous rollbacks to agreement points in case of deadlock. The new calculus is equipped with a compliance relation which is shown to be decidable.Comment: In Proceedings PLACES 2015, arXiv:1602.0325