On symbolic semantics for name-decorated contexts

Under several regards, various of the recently proposed computational paradigms are open-ended, i.e. they may comprise components whose behaviour is not or cannot be fully specified. For instance, applications can be distributed across different administration domains that do not fully disclose their internal business processes to each other, or the dynamics of the system may allow reconfigurations and dynamic bindings whose specification is not available at design time. While a large set of mature design and analysis techniques for closed systems have been developed, their lifting to the open case is not always straightforward. Some existing approaches in the process calculi community are based on the need of proving properties for components that may hold in any, or significantly many, execution environments. Dually, frameworks describing the dynamics of systems with unspecified components have also been presented. In this paper we lay some preliminary ideas on how to extend a symbolic semantics model for open systems in order to deal with name-based calculi. Moreover, we also discuss how the use of a simple type system based on name-decoration for unknown components can improve the expressiveness of the framework. The approach is illustrated on a simple, paradigmatic calculus of web crawlers, which can be understood as a term representation of a simple class of graphs

Intersection types for unbind and rebind

We define a type system with intersection types for an extension of lambda-calculus with unbind and rebind operators. In this calculus, a term with free variables, representing open code, can be packed into an "unbound" term, and passed around as a value. In order to execute inside code, an unbound term should be explicitly rebound at the point where it is used. Unbinding and rebinding are hierarchical, that is, the term can contain arbitrarily nested unbound terms, whose inside code can only be executed after a sequence of rebinds has been applied. Correspondingly, types are decorated with levels, and a term has type decorated with k if it needs k rebinds in order to reduce to a value. With intersection types we model the fact that a term can be used differently in contexts providing different numbers of unbinds. In particular, top-level terms, that is, terms not requiring unbinds to reduce to values, should have a value type, that is, an intersection type where at least one element has level 0. With the proposed intersection type system we get soundness under the call-by-value strategy, an issue which was not resolved by previous type systems.Comment: In Proceedings ITRS 2010, arXiv:1101.410

Reconciling positional and nominal binding

We define an extension of the simply-typed lambda calculus where two different binding mechanisms, by position and by name, nicely coexist. In the former, as in standard lambda calculus, the matching between parameter and argument is done on a positional basis, hence alpha-equivalence holds, whereas in the latter it is done on a nominal basis. The two mechanisms also respectively correspond to static binding, where the existence and type compatibility of the argument are checked at compile-time, and dynamic binding, where they are checked at run-time.Comment: In Proceedings ITRS 2012, arXiv:1307.784

A continuation semantics of interrogatives that accounts for Baker's ambiguity

Wh-phrases in English can appear both raised and in-situ. However, only in-situ wh-phrases can take semantic scope beyond the immediately enclosing clause. I present a denotational semantics of interrogatives that naturally accounts for these two properties. It neither invokes movement or economy, nor posits lexical ambiguity between raised and in-situ occurrences of the same wh-phrase. My analysis is based on the concept of continuations. It uses a novel type system for higher-order continuations to handle wide-scope wh-phrases while remaining strictly compositional. This treatment sheds light on the combinatorics of interrogatives as well as other kinds of so-called A'-movement.Comment: 20 pages; typo fixe

Process algebraic frameworks for the specification and analysis of cryptographic protocols

Two process algebraic approaches for the analysis of cryptographic protocols, namely the spi calculus by Abadi and Gordon and CryptoSPA by Focardi, Gorrieri and Martinelli, are surveyed and compared. We show that the two process algebras have comparable expressive power, by providing an encoding of the former into the latter. We also discuss the relationships among some security properties, i.e., authenticity and secrecy, that have different definitions in the two approaches

Semantika simboličkih ukrasa na makedonskome tradicionalnom pokretnom namještaju iz 19. stoljeća

The analysis of symbolic decoration on movable furniture is a process defined by expressing the inner world of thoughts and ideas through the outside, living world. The furniture and other household equipments were made with high functionality. Functionality of the furniture was the most important, more precisely its aestetics was a result of functionality. The world of the symbolic decoration was personal, intimate or beloged to the family, and although it was conceived and handmade by self-taught carpenter/the host, analyses reveal deep cosmological links of images with the past and tradition. Therefore, the aim of this paper is to analyze the process of creating the decoration and semantics of the Macedonian traditional movable furniture from the 19th century. Researches and analyses were made in the Republic of Macedonia, more specifically in several villages around the mountain of Skopska Crna Gora and in the village Dzepciste from the Tetovo region, and the region of the citty of Veles. Based on measurements of the objects, photos, drawings, foto-documentation, the paper exposed their actual appearance. Based on these drawings, analyses of symbols and forms were made, as well as a deeper analysis of the religious context within which they were made. The analyzes showed that the symbolic decoration of movable furniture in the Macedonian traditional house from the 19th century has its roots in the past as the archetypal signs follow the furniture through the ages. The purpose of this paper was to analyze cosmological pictures of the furniture, to describe them clearly and in the future perhaps be able to apply them in a new modern context.Analiza simboličkih ukrasa na pokretnom namještaju proces je definiran izražavanjem unutarnjeg svijeta misli i ideja prema vanjskome, živom svijetu. Namještaj i ostali proizvodi i uređaji za kućanstvo proizvedeni su tako da budu što funkcionalniji. Funkcionalnost namještaja je najvažnija, a njegova je estetika rezultat funkcionalnosti. Svijet simboličkih ukrasa najčešće je bio osobna, intimna ili obiteljska odrednica, a rezultat je maštovitosti i rada samoukih stolara. Analize otkrivaju duboke kozmološke veze sa slikama iz prošlosti i tradicijom te njihovo ponavljanje u povijesti. Stoga je cilj ovog rada bio analizirati proces stvaranja ukrasa i semantiku makedonskoga tradicionalnog pokretnog namještaja iz 19. stoljeća. Istraživanja i analize obavljeni su u Republici Makedoniji, u nekoliko sela oko planine Skopska Crna Gora, zatim u selu Dzepciste, u regiji oko grada Tetova te u području grada Velesa. Na temelju mjerenja objekata, fotografi ja, crteža i fotodokumentacije, u radu je izložen njihov pravi i stvarni izgled. Na temelju tih crteža obavljene su analize simbola i oblika te dublje analize religijskog konteksta pod utjecajem kojega su ti ukrasi nastali. Analize su pokazale da simbolički ukrasi pokretnog namještaja u makedonskoj tradicijskoj kući iz 19. stoljeća ima korijene u prošlosti, unutar koje se na temelju arhetipskih znakova može pratiti razvoj namještaja kroz stoljeća. Cilj rada bio je jasno opisati analizu kozmološke slike namještaja i tu sliku nekad u budućnosti možda prenijeti u novi, moderni kontekst

Process algebraic frameworks for the specification and ana lysis of cryptographic protocols

Two process algebraic approaches for the analysis of cryptographic protocols, namely the spi calculus by Abadi and Gordon and CryptoSPA by Focardi, Gorrieri and Martinelli, are surveyed and compared. We show that the two process algebras have comparable expressive power, by providing an encoding of the former into the latter. We also discuss the relationships among some security properties, i.e., authenticity and secrecy, that have different definitions in the two approaches