Relating state-based and process-based concurrency through linear logic (full-version)

AbstractThis paper has the purpose of reviewing some of the established relationships between logic and concurrency, and of exploring new ones.Concurrent and distributed systems are notoriously hard to get right. Therefore, following an approach that has proved highly beneficial for sequential programs, much effort has been invested in tracing the foundations of concurrency in logic. The starting points of such investigations have been various idealized languages of concurrent and distributed programming, in particular the well established state-transformation model inspired by Petri nets and multiset rewriting, and the prolific process-based models such as the π-calculus and other process algebras. In nearly all cases, the target of these investigations has been linear logic, a formal language that supports a view of formulas as consumable resources. In the first part of this paper, we review some of these interpretations of concurrent languages into linear logic and observe that, possibly modulo duality, they invariably target a small semantic fragment of linear logic that we call LVobs.In the second part of the paper, we propose a new approach to understanding concurrent and distributed programming as a manifestation of logic, which yields a language that merges those two main paradigms of concurrency. Specifically, we present a new semantics for multiset rewriting founded on an alternative view of linear logic and specifically LVobs. The resulting interpretation is extended with a majority of linear connectives into the language of ω-multisets. This interpretation drops the distinction between multiset elements and rewrite rules, and considerably enriches the expressive power of standard multiset rewriting with embedded rules, choice, replication, and more. Derivations are now primarily viewed as open objects, and are closed only to examine intermediate rewriting states. The resulting language can also be interpreted as a process algebra. For example, a simple translation maps process constructors of the asynchronous π-calculus to rewrite operators. The language of ω-multisets forms the basis for the security protocol specification language MSR 3. With relations to both multiset rewriting and process algebra, it supports specifications that are process-based, state-based, or of a mixed nature, with the potential of combining verification techniques from both worlds. Additionally, its logical underpinning makes it an ideal common ground for systematically comparing protocol specification languages

Office du Niger e Progetto Gezira: da progetti di affermazione coloniale a nuove territorialità

The research I’ve been carrying on sets its main issue on the link between irrigation projects and the territorial outputs in Sahelian-Sudanese region, focusing particularly on the research question about how the territory can be created by the projects themselves and when this process could be identified with a local development process. This paper focuses on two peculiar case studies, as the biggest irrigation projects in the considerated area: Gezira Project in Sudan and Office du Niger in Mali; both present interesting features to pursue a comparative study about their own territorial evolution along with the hydraulic territorialization and the new territoriality. After two research missions on the field, it has been possible to have a complete analysis of the social dynamics on the two project territories, to better understand the processes that have been implemented along with the territorialization and territoriality issues. In the final part of the paper the theoretical framework and the territorial outputs are linked, to better analyze the territorialization process according to the territorial sustainability (in which can be found the economic, social, political and environmental one)

Fare Rigenerazione: Esperienze, Tentativi, Mutamenti

I saggi raccolti in questo volume sono esito di ricerche ed esperienze condotte su alcuni contesti del Friuli Venezia Giulia. Il volume prova a mettere in evidenza l’esigenza di costruire un nuovo racconto capace forse di restituire gli elementi essenziali di un profondo cambiamento dello statuto del progetto contemporaneo, orientato non solo a inseguire i principi della sostenibilità ma anche a rivelare possibilità latenti nello spazio per costruire un nuovo disegno per il futuro delle città

Relating Multiset Rewriting and Process Algebras for Security Protocol Analysis

When formalizing security protocols, different specification languages support very different reasoning methodologies, whose results are not directly or easily comparable. Therefore, establishing clear mappings among different frameworks is highly desirable, as it permits various methodologies to cooperate by interpreting theoretical and practical results of one system into another. In this paper, we examine the relationship between two general verification frameworks: multiset rewriting (MSR) and a process algebra (PA) inspired to CCS and the -calculus. Although defining a simple and general bi-jection between MSR and PA appears difficult, we show that the sublanguages needed to specify cryptographic protocols admit an effective translation that is not only trace-preserving, but also induces a correspondence relation between the two languages. In particular, the correspondence sketched in this paper permits transferring several important trace-based properties such as secrecy and many forms of authentication

A Formal Analysis of Some Properties of Kerberos 5 Using MSR

We give three formalizations of the Kerberos 5 authentication protocol in the Multi-Set Rewriting (MSR) formalism. One is a high-level formalization containing just enough detail to prove authentication and confidentiality properties of the protocol. A second formalization refines this by adding a variety of protocol options; we similarly refine proofs of properties in the first formalization to prove properties of the second formalization. Our third formalization adds timestamps to the first formalization but has not been analyzed extensively. The various proofs make use of rank and corank functions, inspired by work of Schneider in CSP, and provide examples of reasoning about real-world protocols in MSR.We also note some potentially curious protocol behavior; given our positive results, this does not compromise the security of the protocol

Towards an embedding of Graph Transformation in Intuitionistic Linear Logic

Linear logics have been shown to be able to embed both rewriting-based approaches and process calculi in a single, declarative framework. In this paper we are exploring the embedding of double-pushout graph transformations into quantified linear logic, leading to a Curry-Howard style isomorphism between graphs and transformations on one hand, formulas and proof terms on the other. With linear implication representing rules and reachability of graphs, and the tensor modelling parallel composition of graphs and transformations, we obtain a language able to encode graph transformation systems and their computations as well as reason about their properties

Project modules – Prospects for ancient heritage towards ecological transition

For the marginal territories in northeastern Italy, there is a desire to formulate exploratory re-generation projects capable of bridging, through a multidisciplinary approach, the territorialand architectural scales. The concept of a module can serve as the foundation for the entireregenerative process, starting with the recovery and reuse of existing building heritage. Theaim is to employ an architectural module capable of adapting, either as a single unit or whenaggregated, by disassembling the urban fabric and reassembling it into new forms, de-signed to mediate between public and private space, thereby becoming the embodimentof a renewed compositional archetype. The architectural choice is made without predefinedfunctions, allowing for the anticipation of regenerative processes in multiple contexts, op-erating on the potential of indeterminacy, rhythms, and juxtaposition