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Related papers: Homotopy Type Theory in Lean

200 papers

We develop a denotational semantics for general reference types in an impredicative version of guarded homotopy type theory, an adaptation of synthetic guarded domain theory to Voevodsky's univalent foundations. We observe for the first…

Logic in Computer Science · Computer Science 2023-11-22 Jonathan Sterling , Daniel Gratzer , Lars Birkedal

We develop a new, intrinsic, computationally friendly approach to Lie coalgebras through graph coalgebras, which are new and likely to be of independent interest. Our graph coalgebraic approach has advantages both in finding relations…

Algebraic Topology · Mathematics 2009-01-16 Dev Sinha , Ben Walter

Simplicial type theory extends homotopy type theory and equips types with a notion of directed morphisms. A Segal type is defined to be a type in which these directed morphisms can be composed. We show that all higher coherences can be…

Category Theory · Mathematics 2026-01-30 Tom de Jong , Nicolai Kraus , Axel Ljungström

This article proposes an algorithm that constructs a Sullivan minimal model for any simply connected simplicial set with effective homology and thereby allows one to decide algorithmically whether two simply connected spaces represented by…

Algebraic Topology · Mathematics 2025-12-25 Mária Šimková

A type theory is presented that combines (intuitionistic) linear types with type dependency, thus properly generalising both intuitionistic dependent type theory and full linear logic. A syntax and complete categorical semantics are…

Logic in Computer Science · Computer Science 2026-05-07 Matthijs Vákár

In this article we consider the homotopy theory of stratified spaces through a simplicial point of view. We first consider a model category of filtered simplicial sets over some fixed poset $P$, and show that it is a simplicial…

Algebraic Topology · Mathematics 2020-03-24 Sylvain Douteau

We describe a collection of higher homotopy operations which determine the rational homotopy type of a simply-connected space X. These are described in terms of simplicial resolutions of successive approximations (L^k,\alpha} to the Quillen…

Algebraic Topology · Mathematics 2007-05-23 David Blanc

Using the language of homotopy type theory (HoTT), we 1) prove a synthetic version of the classification theorem for covering spaces, and 2) explore the existence of canonical change-of-basepoint isomorphisms between homotopy groups. There…

Algebraic Topology · Mathematics 2024-09-25 Jelle Wemmenhove , Cosmin Manea , Jim Portegies

A brief survey of how classical field theory emerges synthetically in cohesive homotopy type theory. Extended Conference Abstract submitted to the proceedings of the Conference on Type Theory, Homotopy Theory and Univalent Foundations in…

Mathematical Physics · Physics 2013-11-06 Urs Schreiber

Many important theorems in differential topology relate properties of manifolds to properties of their underlying homotopy types -- defined e.g. using the total singular complex or the \v{C}ech nerve of a good open cover. Upon embedding the…

Algebraic Topology · Mathematics 2023-09-06 Adrian Clough

This survey contains the main results in rational homotopy, from the beginning to the most recent ones. It makes the status of the art, gives a short presentation of some areas where rational homotopy has been used, and contains a lot of…

Algebraic Topology · Mathematics 2017-08-18 Yves Félix , Steve Halperin

Postulating an impredicative universe in dependent type theory allows System F style encodings of finitary inductive types, but these fail to satisfy the relevant {\eta}-equalities and consequently do not admit dependent eliminators. To…

Logic in Computer Science · Computer Science 2024-02-22 Steve Awodey , Jonas Frey , Sam Speight

The field of directed type theory seeks to design type theories capable of reasoning synthetically about (higher) categories, by generalizing the symmetric identity types of Martin-L\"of Type Theory to asymmetric hom-types. We articulate…

Category Theory · Mathematics 2025-10-21 Thorsten Altenkirch , Jacob Neumann

We prove a conservativity result for extensional type theories over propositional ones, i.e. dependent type theories with propositional computation rules, or computation axioms, using insights from homotopy type theory. The argument…

Logic · Mathematics 2025-10-01 Matteo Spadetto

Given an algebraic theory $\ct$, a homotopy $\ct$-algebra is a simplicial set where all equations from $\ct$ hold up to homotopy. All homotopy $\ct$-algebras form a homotopy variety. We give a characterization of homotopy varieties…

Category Theory · Mathematics 2007-05-23 J. Rosicky

Pure type systems arise as a generalisation of simply typed lambda calculus. The contemporary development of mathematics has renewed the interest in type theories, as they are not just the object of mere historical research, but have an…

Logic · Mathematics 2014-11-07 Nino Guallart

We prove a conjecture about the constructibility of coinductive types - in the principled form of indexed M-types - in Homotopy Type Theory. The conjecture says that in the presence of inductive types, coinductive types are derivable.…

Logic in Computer Science · Computer Science 2019-07-16 Benedikt Ahrens , Paolo Capriotti , Régis Spadotti

We introduce and study a notion of large homomorphisms on the homotopy lie coalgebra; these homomorphisms are a variant of the large homomorphisms of Levin. As a consequence of our work, we establish new cases of a homotopy lie coalgebra…

Commutative Algebra · Mathematics 2026-05-06 Andrew J. Soto Levins , Ryan Watson

Recently discovered domain-specific formal systems -- specifically homotopy type theory and simplicial type theory -- provide new perspectives on spaces and categories in a natively equivalence-invariant setting. In this note, we expose…

Category Theory · Mathematics 2025-10-20 Emily Riehl

We propose LeanLTL, a unifying framework for linear temporal logics in Lean 4. LeanLTL supports reasoning about traces that represent either infinite or finite linear time. The library allows traditional LTL syntax to be combined with…

Logic in Computer Science · Computer Science 2025-07-03 Eric Vin , Kyle A. Miller , Daniel J. Fremont