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Recent discoveries have been made connecting abstract homotopy theory and the field of type theory from logic and theoretical computer science. This has given rise to a new field, which has been christened "homotopy type theory". In this…

Logic · Mathematics 2012-10-23 Álvaro Pelayo , Michael A. Warren

This paper presents a type theory in which it is possible to directly manipulate $n$-dimensional cubes (points, lines, squares, cubes, etc.) based on an interpretation of dependent type theory in a cubical set model. This enables new ways…

Logic in Computer Science · Computer Science 2016-11-14 Cyril Cohen , Thierry Coquand , Simon Huber , Anders Mörtberg

Martin-L\"of's Intuitionistic Theory of Types is becoming popular for formal reasoning about computer programs. To handle recursion schemes other than primitive recursion, a theory of well-founded relations is presented. Using primitive…

Logic in Computer Science · Computer Science 2008-02-03 Lawrence C. Paulson

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

A fertile field of research in theoretical computer science investigates the representation of general recursive functions in intensional type theories. Among the most successful approaches are: the use of wellfounded relations,…

Logic in Computer Science · Computer Science 2017-01-11 Venanzio Capretta

We present new induction principles for the syntax of dependent type theories, which we call relative induction principles. The result of the induction principle relative to a functor F into the syntax is stable over the codomain of F. We…

Logic in Computer Science · Computer Science 2021-07-20 Rafaël Bocquet , Ambrus Kaposi , Christian Sattler

We construct a left semi-model structure on the category of intensional type theories (precisely, on $\mathrm{CxlCat_{Id,1,\Sigma(,\Pi_{ext})}}$). This presents an $\infty$-category of such type theories; we show moreover that there is an…

Category Theory · Mathematics 2026-02-06 Chris Kapulkin , Peter LeFanu Lumsdaine

We discuss the treatment of initial datatypes and final process types in the wide-spectrum language HasCASL. In particular, we present specifications that illustrate how datatypes and process types arise as bootstrapped concepts using…

Logic in Computer Science · Computer Science 2015-07-01 Lutz Schröder

This paper introduces an expressive class of indexed quotient-inductive types, called QWI types, within the framework of constructive type theory. They are initial algebras for indexed families of equational theories with possibly…

Logic in Computer Science · Computer Science 2023-06-22 Marcelo P. Fiore , Andrew M. Pitts , S. C. Steenkamp

In this article the author endows the functor category [B(Z2),Gpd] with the structure of a type-theoretic fibration category with a univalent universe using the so-called injective model structure. It gives us a new model of Martin-L\"of…

Category Theory · Mathematics 2017-12-12 Anthony Bordg

Higher inductive-inductive types (HIITs) generalize inductive types of dependent type theories in two ways. On the one hand they allow the simultaneous definition of multiple sorts that can be indexed over each other. On the other hand they…

Logic in Computer Science · Computer Science 2023-06-22 Ambrus Kaposi , András Kovács

In classical set theory, there are many equivalent ways to introduce ordinals. In a constructive setting, however, the different notions split apart, with different advantages and disadvantages for each. We consider three different notions…

Logic in Computer Science · Computer Science 2022-08-04 Nicolai Kraus , Fredrik Nordvall Forsberg , Chuangjie Xu

We investigate inductive types in type theory, using the insights provided by homotopy type theory and univalent foundations of mathematics. We do so by introducing the new notion of a homotopy-initial algebra. This notion is defined by a…

Logic · Mathematics 2015-04-22 Steve Awodey , Nicola Gambino , Kristina Sojakova

In this paper, we define indexed type theories which are related to indexed ($\infty$-)categories in the same way as (homotopy) type theories are related to ($\infty$-)categories. We define several standard constructions for such theories…

Category Theory · Mathematics 2023-06-22 Valery Isaev

We develop a homotopy theory for additive categories endowed with endofunctors, analogous to the concept of a model structure. We use it to construct the homotopy theory of a Hovey triple (which consists of two compatible complete cotorsion…

Representation Theory · Mathematics 2017-03-09 Zhi-Wei Li

We study the homotopy theory of a certain type of diagram categories whose vertices are in variable categories with a functorial path, leading to a good calculation of the homotopy category in terms of cofibrant objects. The theory is…

Algebraic Topology · Mathematics 2016-10-04 Joana Cirici

In this paper we examine the natural interpretation of a ramified type hierarchy into Martin-L\"of type theory with an infinite sequence of universes. It is shown that under this predicative interpretation some useful special cases of…

Logic · Mathematics 2017-04-25 Erik Palmgren

We introduce type-theoretic algebraic weak factorisation systems and show how they give rise to homotopy-theoretic models of Martin-L\"of type theory. This is done by showing that the comprehension category associated to a type-theoretic…

Category Theory · Mathematics 2022-06-30 Nicola Gambino , Marco Federico Larrea

Connections between homotopy theory and type theory have recently attracted a lot of attention, with Voevodsky's univalent foundations and the interpretation of Martin-Lof's identity types in Quillen model categories as some of the…

Category Theory · Mathematics 2016-09-21 Benno van den Berg

We define a class of higher inductive types that can be constructed in the category of sets under the assumptions of Zermelo-Fraenkel set theory without the axiom of choice or the existence of uncountable regular cardinals. This class…

Logic · Mathematics 2022-02-07 Andrew Swan