Decidable subtyping for path dependent types

Decidable and Undecidable Fragments of Asynchronous Subtyping for Session Types

Session types are behavioural types for guaranteeing that concurrent programsare free from basic communication errors. Recent work has shown that asyn-chronous session subtyping is undecidable. However, since session types havebecome popular in mainstream programming languages in which asynchronouscommunication is the norm rather than the exception, it is crucial to detect<l...

Subtyping dependent types

The need for subtyping in type-systems with dependent types has been realized for some years. But it is hard to prove that systems combining the two features have fundamental properties such as subject reduction. Here we investigate a subtyping extension of the system λP, which is an abstract version of the type system of the Edinburgh Logicalversion of the type system of the Edinburgh Logical ...

Structural Subtyping of Non-Recursive Types is Decidable

We show that the first-order theory of structural subtyping of non-recursive types is decidable, as a consequence of a more general result on the decidability of term powers of decidable theories. Let be a language consisting of function symbols and let C (with a finite or infinite domain C) be an L-structure where L is a language consisting of relation symbols. We introduce the notion of -term...

Subtyping Parametric and Dependent Types

Decidable Higher Order Subtyping

This paper establishes the decidability of typechecking in Fω ∧ , a typed lambda calculus combining higher-order polymorphism, subtyping, and intersection types. It contains the first proof of decidability of subtyping for a higher-order system.