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Constructor subtyping

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Detalhes bibliográficos
Resumo:Constructor subtyping is a form of subtyping in which an inductive type A is viewed as a subtype of another inductive type B if B has more constructors than A. Its (potential) uses include proof assistants and functional programming languages. In this paper, we introduce and study the properties of a simply typed lambda-calculus with record types and datatypes, and which supports record subtyping and constructor subtyping. In the first part of the paper, we show that the calculus is confluent and strongly normalizing. In the second part of the paper, we show that the calculus admits a well-behaved theory of canonical inhabitants, provided one adopts expansive extensionality rules, including eta-expansion, surjective pairing, and a suitable expansion rule for datatypes. Finally, in the third part of the paper, we extend our calculus with unbounded recursion and show that confluence is preserved.
Autores principais:Barthe, Gilles Jacques Denis
Outros Autores:Frade, M. J.
Assunto:Type theory Lambda-calculus Subtyping
Ano:1999
País:Portugal
Tipo de documento:comunicação em conferência
Tipo de acesso:acesso aberto
Instituição associada:Universidade do Minho
Idioma:inglês
Origem:RepositóriUM - Universidade do Minho
Descrição
Resumo:Constructor subtyping is a form of subtyping in which an inductive type A is viewed as a subtype of another inductive type B if B has more constructors than A. Its (potential) uses include proof assistants and functional programming languages. In this paper, we introduce and study the properties of a simply typed lambda-calculus with record types and datatypes, and which supports record subtyping and constructor subtyping. In the first part of the paper, we show that the calculus is confluent and strongly normalizing. In the second part of the paper, we show that the calculus admits a well-behaved theory of canonical inhabitants, provided one adopts expansive extensionality rules, including eta-expansion, surjective pairing, and a suitable expansion rule for datatypes. Finally, in the third part of the paper, we extend our calculus with unbounded recursion and show that confluence is preserved.