597 research outputs found
The theory of classification part 16: rules of extension and the typing of inheritance
The mechanism of inheritance, keeping in view the constraints on what may or may not be added to a class during inheritance, is examined. It is considered reasonable to to think of the merger of two record types as the set union of their respective sets of maplets. In the subtyping model, it is suggested to consider the possibility that fields of different types may be merged. It is possible to construct Derived record types using simple set union ∩ to merge the two sets of type signatures in the corresponding Base and Extra type-records
Plurals: individuals and sets in a richly typed semantics
We developed a type-theoretical framework for natural lan- guage semantics
that, in addition to the usual Montagovian treatment of compositional
semantics, includes a treatment of some phenomena of lex- ical semantic:
coercions, meaning, transfers, (in)felicitous co-predication. In this setting
we see how the various readings of plurals (collective, dis- tributive,
coverings,...) can be modelled
Foundations of Session Types and Behavioural Contracts
International audienceBehavioural type systems, usually associated to concurrent or distributed computations, encompass concepts such as interfaces, communication protocols, and contracts, in addition to the traditional input/output operations. The behavioural type of a software component specifies its expected patterns of interaction using expressive type languages, so that types can be used to determine automatically whether the component interacts correctly with other components. Two related important notions of behavioural types are those of session types and behavioural contracts. This paper surveys the main accomplishments of the last twenty years within these two approaches
Relational semantics of linear logic and higher-order model-checking
In this article, we develop a new and somewhat unexpected connection between
higher-order model-checking and linear logic. Our starting point is the
observation that once embedded in the relational semantics of linear logic, the
Church encoding of any higher-order recursion scheme (HORS) comes together with
a dual Church encoding of an alternating tree automata (ATA) of the same
signature. Moreover, the interaction between the relational interpretations of
the HORS and of the ATA identifies the set of accepting states of the tree
automaton against the infinite tree generated by the recursion scheme. We show
how to extend this result to alternating parity automata (APT) by introducing a
parametric version of the exponential modality of linear logic, capturing the
formal properties of colors (or priorities) in higher-order model-checking. We
show in particular how to reunderstand in this way the type-theoretic approach
to higher-order model-checking developed by Kobayashi and Ong. We briefly
explain in the end of the paper how his analysis driven by linear logic results
in a new and purely semantic proof of decidability of the formulas of the
monadic second-order logic for higher-order recursion schemes.Comment: 24 pages. Submitte
A theory of contracts for web services
<p>Contracts are behavioural descriptions of Web services. We devise a theory of contracts that formalises the compatibility of a client to a service, and the safe replacement of a service with another service. The use of contracts statically ensures the successful completion of every possible interaction between compatible clients and services.</p>
<p>The technical device that underlies the theory is the definition of filters, which are explicit coercions that prevent some possible behaviours of services and, in doing so, they make services compatible with different usage scenarios. We show that filters can be seen as proofs of a sound and complete subcontracting deduction system which simultaneously refines and extends Hennessy's classical axiomatisation of the must testing preorder. The relation is decidable and the decision algorithm is obtained via a cut-elimination process that proves the coherence of subcontracting as a logical system.</p>
<p>Despite the richness of the technical development, the resulting approach is based on simple ideas and basic intuitions. Remarkably, its application is mostly independent of the language used to program the services or the clients. We also outline the possible practical impact of such a work and the perspectives of future research it opens.</p>
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