Ines Margaria

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This paper gives a complete characterisation of type isomorphism definable by terms of a λ-calculus in a type system with intersection and union types. Type isomorphism is usually proved using a form of Inversion Lemma to relate terms and types. Currently in the literature no inversion lemma for intersection and union types is provided. Moreover, the(More)
The definition of filter model is extended to a variant of Ambient Calculus: Safe Ambient Calculus, introduced for developing an algebraic theory for a bisimulation-based behavioral equivalence. The types are constructed by means of elementary and higher-order actions, that define the moves processes can do. Entailment rules for types allow to translate the(More)
Type isomorphism is useful for retrieving library components, since a function in a library can have a type different from, but isomorphic to, the one expected by the user. Moreover type isomorphism gives for free the coercion required to include the function in the user program with the right type. The present paper faces the problem of type isomorphism in(More)
Type isomorphism for intersection types is quite odd, since it is not a congruence and it does not extend type equality in the standard interpretation of types. The lack of congruence is due to the proof theoretic nature of the intersection introduction rule, which requires the same term to be the subject of both premises. A partial congruence can be(More)
In this paper we investigate type isomorphism in a λ-calculus with intersection and union types. It is known that in λ-calculus, the isomorphism between two types is realised by an invertible term. Notably all invertible terms are linear terms. Type isomorphism is usually proved using a form of Inversion Lemma to relate terms and types. Currently in the(More)