Intensionality, extensionality, and proof irrelevance in modal type theory
Intensionality, extensionality, and proof irrelevance in modal type theory
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模态类型理论中的内涵性、外延性和证明无关性
DOI:
10.1109/lics.2001.932499
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发表时间:
2001
期刊:
影响因子:
--
通讯作者:
F. Pfenning
中科院分区:
文献类型:
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作者:
F. Pfenning
We develop a uniform type theory that integrates intensionality, extensionality and proof irrelevance as judgmental concepts. Any object may be treated intensionally (subject only to /spl alpha/-conversion), extensionally (subject also to /spl beta//spl eta/-conversion), or as irrelevant (equal to any other object at the same type), depending on where it occurs. Modal restrictions developed by R. Harper et al. (2000) for single types are generalized and employed to guarantee consistency between these views of objects. Potential applications are in logical frameworks, functional programming and the foundations of first-order modal logics. Our type theory contrasts with previous approaches that, a priori, distinguished propositions (whose proofs are all identified - only their existence is important) from specifications (whose implementations are subject to some definitional equalities).