2026-07-24T05:02:12Z https://drops.dagstuhl.de/oai

oai:drops-oai.dagstuhl.de:14265 2024-03-06T10:53:17Z ddc:004 open_access

What’s Decidable About (Atomic) Polymorphism? Pistone, Paolo Tranchini, Luca Atomic System F Predicative Polymorphism ML-Polymorphism Type-Checking Contextual Equivalence Free Theorems Due to the undecidability of most type-related properties of System F like type inhabitation or type checking, restricted polymorphic systems have been widely investigated (the most well-known being ML-polymorphism). In this paper we investigate System Fat, or atomic System F, a very weak predicative fragment of System F whose typable terms coincide with the simply typable ones. We show that the type-checking problem for Fat is decidable and we propose an algorithm which sheds some new light on the source of undecidability in full System F. Moreover, we investigate free theorems and contextual equivalence in this fragment, and we show that the latter, unlike in the simply typed lambda-calculus, is undecidable. Schloss Dagstuhl – Leibniz-Zentrum für Informatik Paolo Pistone and Luca Tranchini 2021 Is Part Of LIPIcs, Volume 195, 6th International Conference on Formal Structures for Computation and Deduction (FSCD 2021) InProceedings Text doc-type:ResearchArticle publishedVersion application/pdf doi:10.4230/LIPIcs.FSCD.2021.27 urn:nbn:de:0030-drops-142652 https://drops.dagstuhl.de/entities/document/10.4230/LIPIcs.FSCD.2021.27 eng https://creativecommons.org/licenses/by/4.0/legalcode