We present a general form of temporal effects for recursive types. Temporal effects have been adopted by effect systems to verify both linear-time temporal safety and liveness properties of higher-order programs with recursive functions. A challenge in a ...

Proof assistants based on dependent type theory, such as Coq, Lean and Agda, use different universes to classify types, typically combining a predicative hierarchy of universes for computationally-relevant types, and an impredicative universe of proof-...

Modern mainstream programming languages, such as TypeScript, Flow, and Scala, have polymorphic type systems enriched with intersection and union types. These languages implement variants of bidirectional higher-rank polymorphic type inference, which was ...

We present ZipML, a new path-based type system for a fully fledged ML-module language that avoids the signature avoidance problem. This is achieved by introducing floating fields, which act as additional fields of a signature, invisible to the user but ...

Many of today’s message-passing systems not only require messages to be exchanged in a certain order but also to happen at a certain time or within a certain time window. Such correctness conditions are particularly prominent in Internet of Things (IoT) ...

Graphs and their algorithms are fundamental to computer science, but they can be difficult to formalise, especially in dependently-typed proof assistants. Part of the problem is that graphs aren’t as well-behaved as inductive data types like trees or ...

Constructive type theory combines logic and programming in one language. This is useful both for reasoning about programs written in type theory, as well as for reasoning about other programming languages inside type theory. It is well-known that it is ...

We introduce a type system for the Quipper language designed to derive upper bounds on the size of the circuits produced by the typed program. This size can be measured according to various metrics, including width, depth and gate count, but also ...

Separation logic has become an important tool for formally capturing and reasoning about the ownership patterns of imperative programs, originally for paper proof, and now the foundation for industrial static analyses and multiple proof tools. However, ...

Multiparty session types (MPST) provide a type discipline for ensuring communication safety, deadlock-freedom and liveness for multiple concurrently running participants. The original formulation of MPST takes the top-down approach, where a global type ...

Many programming languages need to check whether two recursive types are in a subtyping relation. Traditionally recursive types are modelled in two different ways: equi- or iso- recursive types. While efficient algorithms for subtyping equi-recursive ...

We present a novel analysis of the fundamental Löb induction principle from guarded recursion. Taking advantage of recent work in modal type theory and univalent foundations, we derive Löb induction from a simpler and more conceptual set of primitives. ...

Structure editors operate directly on a program’s syntactic tree structure. At first glance, this allows for the exciting possibility that such an editor could enforce correctness properties: programs could be well-formed and sometimes even well-typed by ...

We present DRFcaml, an extension of OCaml's type system that guarantees data race freedom for multi-threaded OCaml programs while retaining backward compatibility with existing sequential OCaml code. We build on recent work of Lorenzen et al., who extend ...

In this paper, we introduce DeLaM, a dependent layered modal type theory which enables meta-programming in Martin-Löf type theory (MLTT) with recursion principles on open code. DeLaM includes three layers: the layer of static syntax objects of MLTT ...

In this paper, we develop and study the following perspective -- just as higher-order functions give exponentials, higher-order continuations give coexponentials. From this, we design a language that combines exponentials and coexponentials, producing a ...

Embedding Multimode Type Theory (MTT) as a library enables the usage of additional reasoning principles in off-the-shelf proof assistants without risking soundness or compatibility. Moreover, by interpreting embedded MTT terms in an internally ...

The Dependent Calculus of Indistinguishability (DCOI) uses dependency tracking to identify irrelevant arguments and uses indistinguishability during type conversion to enable proof irrelevance, supporting run-time and compile-time irrelevance with the ...

Model checking is one of the successful program verification methodologies. Since the seminal work by Ong, the model checking of higher-order programs―called higher-order model checking, or HOMC for short―has gained attention. It is also crucial for ...

The resurgence of Datalog in the last two decades has led to a multitude of new Datalog systems. These systems explore novel ideas for improving Datalog's programmability and performance, making important contributions to the field. Unfortunately, the ...