All -toposes have strict univalent universes

M Shulman - arXiv preprint arXiv:1904.07004, 2019 - arxiv.org
We prove the conjecture that any Grothendieck $(\infty, 1) $-topos can be presented by a
Quillen model category that interprets homotopy type theory with strict univalent universes …

Multimodal dependent type theory

D Gratzer, GA Kavvos, A Nuyts, L Birkedal - Proceedings of the 35th …, 2020 - dl.acm.org
We introduce MTT, a dependent type theory which supports multiple modalities. MTT is
parametrized by a mode theory which specifies a collection of modes, modalities, and …

Brouwer's fixed-point theorem in real-cohesive homotopy type theory

M Shulman - Mathematical Structures in Computer Science, 2018 - cambridge.org
We combine homotopy type theory with axiomatic cohesion, expressing the latter internally
with a version of 'adjoint logic'in which the discretization and codiscretization modalities are …

Normalization for cubical type theory

J Sterling, C Angiuli - 2021 36th Annual ACM/IEEE Symposium …, 2021 - ieeexplore.ieee.org
We prove normalization for (univalent, Cartesian) cubical type theory, closing the last major
open problem in the syntactic metatheory of cubical type theory. Our normalization result is …

A graded modal dependent type theory with a universe and erasure, formalized

A Abel, NA Danielsson, O Eriksson - Proceedings of the ACM on …, 2023 - dl.acm.org
We present a graded modal type theory, a dependent type theory with grades that can be
used to enforce various properties of the code. The theory has Π-types, weak and strong Σ …

Normalization for multimodal type theory

D Gratzer - Proceedings of the 37th Annual ACM/IEEE Symposium …, 2022 - dl.acm.org
We prove normalization for MTT, a general multimodal dependent type theory capable of
expressing modal type theories for guarded recursion, internalized parametricity, and …

The HoTT library: a formalization of homotopy type theory in Coq

A Bauer, J Gross, PLF Lumsdaine, M Shulman… - Proceedings of the 6th …, 2017 - dl.acm.org
We report on the development of the HoTT library, a formalization of homotopy type theory in
the Coq proof assistant. It formalizes most of basic homotopy type theory, including …

Logical relations as types: Proof-relevant parametricity for program modules

J Sterling, R Harper - Journal of the ACM (JACM), 2021 - dl.acm.org
The theory of program modules is of interest to language designers not only for its practical
importance to programming, but also because it lies at the nexus of three fundamental …

Semantics of higher inductive types

PLF Lumsdaine, M Shulman - Mathematical Proceedings of the …, 2020 - cambridge.org
Higher inductive types are a class of type-forming rules, introduced to provide basic (and not-
so-basic) homotopy-theoretic constructions in a type-theoretic style. They have proven very …

A cost-aware logical framework

Y Niu, J Sterling, H Grodin, R Harper - Proceedings of the ACM on …, 2022 - dl.acm.org
We present calf, ac ost-a ware l ogical f ramework for studying quantitative aspects of
functional programs. Taking inspiration from recent work that reconstructs traditional aspects …