论文标题

transpension:PI-Type的右伴侣

Transpension: The Right Adjoint to the Pi-type

论文作者

Nuyts, Andreas, Devriese, Dominique

论文摘要

依赖类型理论的预局部模型已成功地应用于模型,参数性和指示,守护和名义类型理论。有很大的兴趣对这些预局部模型的内部化方面进行了浓厚的兴趣,以使结果语言更具表现力,或者是为了在内部进行进一步的推理,从而可以更大的抽象,有时甚至是自动验证。尽管预局部模型的结构在很大程度上遵循了一种共同的模式,但内在化的方法却没有。在整个文献中,各种内部的预易eaf操作员($ \ surd $,$φ/\ Mathsf {ltengion} $,$ψ/\ Mathsf {gel} $,$ \ Mathsf {glue} $,$ \ MATHSF {WELD} $,$ \ MATHSF,$ \ MATHSF {MATHSF {MATHSF {MATHSF {MATHSF {MATHSF {MATHSF {MATHSF {MATHSF)表达。此外,其中一些要求类型为形状的变量(可代表的预毛,例如间隔)。我们提出了一种新型类型的前身,即移动类型,该类型与形状上的通用定量恰恰相伴。它的结构类似于Hott中悬架类型的依赖版本。我们提供一般的打字规则和基本类别函子称为乘数的语义语义。形状变量的结构规则和转载类型的某些方面取决于乘数的特征。我们演示了如何合并转置类型和严格的公理,以实现所有方面并改善上述一些内部化操作员(对于本地新名称而没有正式索赔)。

Presheaf models of dependent type theory have been successfully applied to model HoTT, parametricity, and directed, guarded and nominal type theory. There has been considerable interest in internalizing aspects of these presheaf models, either to make the resulting language more expressive, or in order to carry out further reasoning internally, allowing greater abstraction and sometimes automated verification. While the constructions of presheaf models largely follow a common pattern, approaches towards internalization do not. Throughout the literature, various internal presheaf operators ($\surd$, $Φ/\mathsf{extent}$, $Ψ/\mathsf{Gel}$, $\mathsf{Glue}$, $\mathsf{Weld}$, $\mathsf{mill}$, the strictness axiom and locally fresh names) can be found and little is known about their relative expressivenes. Moreover, some of these require that variables whose type is a shape (representable presheaf, e.g. an interval) be used affinely. We propose a novel type former, the transpension type, which is right adjoint to universal quantification over a shape. Its structure resembles a dependent version of the suspension type in HoTT. We give general typing rules and a presheaf semantics in terms of base category functors dubbed multipliers. Structural rules for shape variables and certain aspects of the transpension type depend on characteristics of the multiplier. We demonstrate how the transpension type and the strictness axiom can be combined to implement all and improve some of the aforementioned internalization operators (without formal claim in the case of locally fresh names).

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