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arXiv · 2307.13661

Parametric Subtyping for Structural Parametric Polymorphism

Henry DeYoung·Andreia Mordido·Frank Pfenning·Ankush Das
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Abstract

We study the interaction of structural subtyping with parametric polymorphism and recursively defined type constructors. Although structural subtyping is undecidable in this setting, we describe a notion of parametricity for type constructors and then exploit it to define parametric subtyping, a conceptually simple, decidable, and expressive fragment of structural subtyping that strictly generalizes rigid subtyping. We present and prove correct an effective saturation-based decision procedure for parametric subtyping, demonstrating its applicability using a variety of examples. We also provide an implementation of this decision procedure online.

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Henry DeYoung, Andreia Mordido, Frank Pfenning, Ankush Das. 2023-07-25. Parametric Subtyping for Structural Parametric Polymorphism. https://arxiv.org/abs/2307.13661

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