THE GUARDED LAMBDA-CALCULUS PROGRAMMING AND REASONING WITH GUARDED RECURSION FOR COINDUCTIVE TYPES
THE GUARDED LAMBDA-CALCULUS PROGRAMMING AND REASONING WITH GUARDED RECURSION FOR COINDUCTIVE TYPES
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DOI:
10.2168/lmcs-12(3:7)2016
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发表时间:
2016-01-01
影响因子:
0.6
通讯作者:
Birkedal, Lars
中科院分区:
文献类型:
--
作者:
Clouston, Ranald;Bizjak, Ales;Birkedal, Lars
We present the guarded lambda-calculus, an extension of the simply typed lambda-calculus with guarded recursive and coinductive types. The use of guarded recursive types ensures the productivity of well-typed programs. Guarded recursive types may be transformed into coinductive types by a type-former inspired by modal logic and Atkey-McBride clock quantification, allowing the typing of acausal functions. We give a call-by-name operational semantics for the calculus, and define adequate denotational semantics in the topos of trees. The adequacy proof entails that the evaluation of a program always terminates. We introduce a program logic with Lob induction for reasoning about the contextual equivalence of programs. We demonstrate the expressiveness of the calculus by showing the definability of solutions to Rutten's behavioural differential equations.