Relating Church-Style and Curry-Style Subtyping

Type theories with higher-order subtyping or singleton types are examples of systems where computation rules for variables are affected by type information in the context. A complication for these systems is that bounds declared in the context do not interact well with the logical relation proof of completeness or termination. This paper proposes a natural modification to the type syntax for F-Omega-Sub, adding variable's bound to the variable type constructor, thereby separating the computational behavior of the variable from the context. The algorithm for subtyping in F-Omega-Sub can then be given on types without context or kind information. As a consequence, the metatheory follows the general approach for type systems without computational information in the context, including a simple logical relation definition without Kripke-style indexing by context. This new presentation of the system is shown to be equivalent to the traditional presentation without bounds on the variable type constructor.Comment: In Proceedings ITRS 2010, arXiv:1101.410

Higher-order subtyping and its decidability

AbstractWe define the typed lambda calculus Fω∧ (F-omega-meet), a natural generalization of Girard's system Fω (F-omega) with intersection types and bounded polymorphism. A novel aspect of our presentation is the use of term rewriting techniques to present intersection types, which clearly splits the computational semantics (reduction rules) from the syntax (inference rules) of the system. We establish properties such as Church-Rosser for the reduction relation on types and terms, and strong normalization for the reduction on types. We prove that types are preserved by computation (subject reduction), and that the system satisfies the minimal types property. We define algorithms for type checking and subtype checking. The development culminates with the proof of decidability of typing in Fω∧, containing the first proof of decidability of subtyping of a higher-order lambda calculus with subtyping

Correspondence assertions for process synchronization in concurrent communications

High-level specification of patterns of communications such as protocols can be modeled elegantly by means of session types. However, a number of examples suggest that session types fall short when finer precision on protocol specification is required. In order to increase the expressiveness of session types we appeal to the theory of correspondence assertions. The resulting type discipline augments the types of long term channels with effects and thus yields types which may depend on messages read or written earlier within the same session. We prove that evaluation preserves typability and that well-typed processes are safe. Also, we illustrate how the resulting theory allows us to address the shortcomings present in the pure theory of session types.Laboratorio de Investigación y Formación en Informática Avanzad

Correspondence assertions for process synchronization in concurrent communications

High-level specification of patterns of communications such as protocols can be modeled elegantly by means of session types. However, a number of examples suggest that session types fall short when finer precision on protocol specification is required. In order to increase the expressiveness of session types we appeal to the theory of correspondence assertions. The resulting type discipline augments the types of long term channels with effects and thus yields types which may depend on messages read or written earlier within the same session. We prove that evaluation preserves typability and that well-typed processes are safe. Also, we illustrate how the resulting theory allows us to address the shortcomings present in the pure theory of session types.Laboratorio de Investigación y Formación en Informática Avanzad

Parallel BioScape: A Stochastic and Parallel Language for Mobile and Spatial Interactions

BioScape is a concurrent language motivated by the biological landscapes found at the interface of biology and biomaterials. It has been motivated by the need to model antibacterial surfaces, biofilm formation, and the effect of DNAse in treating and preventing biofilm infections. As its predecessor, SPiM, BioScape has a sequential semantics based on Gillespie's algorithm, and its implementation does not scale beyond 1000 agents. However, in order to model larger and more realistic systems, a semantics that may take advantage of the new multi-core and GPU architectures is needed. This motivates the introduction of parallel semantics, which is the contribution of this paper: Parallel BioScape, an extension with fully parallel semantics.Comment: In Proceedings MeCBIC 2012, arXiv:1211.347

Boxed ambients with communication interfaces

We define BACI (Boxed Ambients with Communication Interfaces), an ambient calculus with a flexible communication policy. Traditionally, typed ambient calculi have a fixed communication policy determining the kind of information that can be exchanged with a parent ambient, even though mobility changes the parent. BACI lifts that restriction, allowing different communication policies with different parents during computation. Furthermore, BACI separates communication and mobility by making the channels of communication between ambients explicit. In contrast with other typed ambient calculi where communication policies are global, each ambient in BACI is equipped with a description of the communication policies ruling its information exchange with parent and child ambients. The communication policies of ambients increase when they move: more precisely, when an ambient enters another ambient, the entering ambient and the host ambient can exchange their communication ports and agree on the kind of information to be exchanged. This information is recorded locally in both ambients. We show the type-soundness of BACI, proving that it satisfies the subject reduction property, and we study its behavioural semantics by means of a labelled transition syste

A Calculus of Located Entities

Comment: In Proceedings DCM 2013, arXiv:1403.768

Correspondence assertions for process synchronization in concurrent communications

High-level specification of patterns of communications such as protocols can be modeled elegantly by means of session types. However, a number of examples suggest that session types fall short when finer precision on protocol specification is required. In order to increase the expressiveness of session types we appeal to the theory of correspondence assertions. The resulting type discipline augments the types of long term channels with effects and thus yields types which may depend on messages read or written earlier within the same session. We prove that evaluation preserves typability and that well-typed processes are safe. Also, we illustrate how the resulting theory allows us to address the shortcomings present in the pure theory of session types.Laboratorio de Investigación y Formación en Informática Avanzad

Typechecking safe process synchronization

Session types describe the interactions between two parties within multi-party communications. They constitute a communication protocol in the sense that the order and type of interactions between two parties are specified. For their part, correspondence assertions provide a mechanism for synchronization. When session types and correspondence assertions are combined, they are able to describe synchronization across different communication sessions, yielding a rich language for imposing expressive interaction patterns in multi-party communications. This paper studies the typechecking problem for Iris, a typed π-calculus that combines session types and correspondence assertions. We define a typechecking algorithm and prove that it is sound and complete with respect to the typing rules. Furthermore, we show that the typing system satisfies the minimum effects property. Although session types have been extensively studied in the past few years, to our knowledge this is the first proof of decidability of typechecking for a type system with session types.Facultad de Informátic

BioScape: A Modeling and Simulation Language for Bacteria-Materials Interactions

We design BioScape, a concurrent language for the stochastic simulation of biological and bio-materials processes in a reactive environment in 3D space. BioScape is based on the Stochastic Pi-Calculus, and it is motivated by the need for individual-based, continuous motion, and continuous space simulation in modeling complex bacteria-materials interactions. Our driving example is a bio-triggered drug delivery system for infection-resistant medical implants. Our models in BioScape will help in identifying biological targets and materials strategies to treat biomaterials associated bacterial infections. The novel aspects of BioScape include syntactic primitives to declare the scope in space where species can move, diffusion rate, shape, and reaction distance, and an operational semantics that deals with the specifics of 3D locations, verifying reaction distance, and featuring random movement. We define a translation from BioScape to 3π and prove its soundness with respect to the operational semantics.Fil: Compagnoni, Adriana. Stevens Institute of Technology; Estados UnidosFil: Sharma, Vishaka. Stevens Institute of Technology; Estados UnidosFil: Bao, Yifei. Stevens Institute of Technology; Estados UnidosFil: Libera, Matthew. Stevens Institute of Technology; Estados UnidosFil: Sukhishvili, Svetlana. Stevens Institute of Technology; Estados UnidosFil: Bidinger, Philippe. VERIMAG; FranciaFil: Boglio, Livio. Universita Di Torino; ItaliaFil: Bonelli, Eduardo Augusto. Universidad Nacional de Quilmes. Departamento de Ciencia y Tecnologia; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin