Partiality, revisited: the partiality monad as a quotient inductive-inductive type

Capretta's delay monad can be used to model partial computations, but it has the ``wrong'' notion of built-in equality, strong bisimilarity. An alternative is to quotient the delay monad by the ``right''notion of equality, weak bisimilarity. However, recent work by Chapman e...

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Main Authors: Altenkirch, Thorsten, Danielson, Nils Anders, Kraus, Nicolai
Format: Conference or Workshop Item
Published: 2016
Online Access:https://eprints.nottingham.ac.uk/41533/
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author Altenkirch, Thorsten
Danielson, Nils Anders
Kraus, Nicolai
author_facet Altenkirch, Thorsten
Danielson, Nils Anders
Kraus, Nicolai
author_sort Altenkirch, Thorsten
building Nottingham Research Data Repository
collection Online Access
description Capretta's delay monad can be used to model partial computations, but it has the ``wrong'' notion of built-in equality, strong bisimilarity. An alternative is to quotient the delay monad by the ``right''notion of equality, weak bisimilarity. However, recent work by Chapman et al. suggests that it is impossible to define a monad structure on the resulting construction in common forms of type theory without assuming (instances of) the axiom of countable choice. Using an idea from homotopy type theory---a higher inductive-inductive type---we construct a partiality monad without relying on countable choice. We prove that, in the presence of countable choice, our partiality monad is equivalent to the delay monad quotiented by weak bisimilarity. Furthermore we outline several applications.
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format Conference or Workshop Item
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institution University of Nottingham Malaysia Campus
institution_category Local University
last_indexed 2025-11-14T19:45:44Z
publishDate 2016
recordtype eprints
repository_type Digital Repository
spelling nottingham-415332020-05-04T18:24:43Z https://eprints.nottingham.ac.uk/41533/ Partiality, revisited: the partiality monad as a quotient inductive-inductive type Altenkirch, Thorsten Danielson, Nils Anders Kraus, Nicolai Capretta's delay monad can be used to model partial computations, but it has the ``wrong'' notion of built-in equality, strong bisimilarity. An alternative is to quotient the delay monad by the ``right''notion of equality, weak bisimilarity. However, recent work by Chapman et al. suggests that it is impossible to define a monad structure on the resulting construction in common forms of type theory without assuming (instances of) the axiom of countable choice. Using an idea from homotopy type theory---a higher inductive-inductive type---we construct a partiality monad without relying on countable choice. We prove that, in the presence of countable choice, our partiality monad is equivalent to the delay monad quotiented by weak bisimilarity. Furthermore we outline several applications. 2016-12-22 Conference or Workshop Item PeerReviewed Altenkirch, Thorsten, Danielson, Nils Anders and Kraus, Nicolai (2016) Partiality, revisited: the partiality monad as a quotient inductive-inductive type. In: FoSSaCs 2017, 24-29 April 2017, Uppsala, Sweden. (In Press)
spellingShingle Altenkirch, Thorsten
Danielson, Nils Anders
Kraus, Nicolai
Partiality, revisited: the partiality monad as a quotient inductive-inductive type
title Partiality, revisited: the partiality monad as a quotient inductive-inductive type
title_full Partiality, revisited: the partiality monad as a quotient inductive-inductive type
title_fullStr Partiality, revisited: the partiality monad as a quotient inductive-inductive type
title_full_unstemmed Partiality, revisited: the partiality monad as a quotient inductive-inductive type
title_short Partiality, revisited: the partiality monad as a quotient inductive-inductive type
title_sort partiality, revisited: the partiality monad as a quotient inductive-inductive type
url https://eprints.nottingham.ac.uk/41533/