An extended type system with lambda-typed lambda-expressions

We present the system $\mathtt{d}$, an extended type system with lambda-typed lambda-expressions. It is related to type systems originating from the Automath project. $\mathtt{d}$ extends existing lambda-typed systems by an existential abstraction operator as well as propositional operators. $\beta$...

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Main Author: Matthias Weber
Format: Article
Language:English
Published: Logical Methods in Computer Science e.V. 2020-12-01
Series:Logical Methods in Computer Science
Subjects:
Online Access:https://lmcs.episciences.org/4409/pdf
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author Matthias Weber
author_facet Matthias Weber
author_sort Matthias Weber
collection DOAJ
description We present the system $\mathtt{d}$, an extended type system with lambda-typed lambda-expressions. It is related to type systems originating from the Automath project. $\mathtt{d}$ extends existing lambda-typed systems by an existential abstraction operator as well as propositional operators. $\beta$-reduction is extended to also normalize negated expressions using a subset of the laws of classical negation, hence $\mathtt{d}$ is normalizing both proofs and formulas which are handled uniformly as functional expressions. $\mathtt{d}$ is using a reflexive type axiom for a constant $\tau$ to which no function can be typed. Some properties are shown including confluence, subject reduction, uniqueness of types, strong normalization, and consistency. We illustrate how, when using $\mathtt{d}$, due to its limited logical strength, additional axioms must be added both for negation and for the mathematical structures whose deductions are to be formalized.
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spelling doaj.art-5bf114c91ef24461a530a7d1b302e6832024-03-08T10:32:05ZengLogical Methods in Computer Science e.V.Logical Methods in Computer Science1860-59742020-12-01Volume 16, Issue 410.23638/LMCS-16(4:12)20204409An extended type system with lambda-typed lambda-expressionsMatthias WeberWe present the system $\mathtt{d}$, an extended type system with lambda-typed lambda-expressions. It is related to type systems originating from the Automath project. $\mathtt{d}$ extends existing lambda-typed systems by an existential abstraction operator as well as propositional operators. $\beta$-reduction is extended to also normalize negated expressions using a subset of the laws of classical negation, hence $\mathtt{d}$ is normalizing both proofs and formulas which are handled uniformly as functional expressions. $\mathtt{d}$ is using a reflexive type axiom for a constant $\tau$ to which no function can be typed. Some properties are shown including confluence, subject reduction, uniqueness of types, strong normalization, and consistency. We illustrate how, when using $\mathtt{d}$, due to its limited logical strength, additional axioms must be added both for negation and for the mathematical structures whose deductions are to be formalized.https://lmcs.episciences.org/4409/pdfcomputer science - logic in computer science
spellingShingle Matthias Weber
An extended type system with lambda-typed lambda-expressions
Logical Methods in Computer Science
computer science - logic in computer science
title An extended type system with lambda-typed lambda-expressions
title_full An extended type system with lambda-typed lambda-expressions
title_fullStr An extended type system with lambda-typed lambda-expressions
title_full_unstemmed An extended type system with lambda-typed lambda-expressions
title_short An extended type system with lambda-typed lambda-expressions
title_sort extended type system with lambda typed lambda expressions
topic computer science - logic in computer science
url https://lmcs.episciences.org/4409/pdf
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