Search Results

Documents authored by Pédrot, Pierre-Marie

Document
DOI: 10.4230/LIPIcs.FSCD.2026.5
Not Choosing Is Still a Choice: Constructive mathematics without any choice

Authors: Martin Baillon, Yannick Forster, Dominik Kirst, Assia Mahboubi, and Pierre-Marie Pédrot

Published in: LIPIcs, Volume 378, 11th International Conference on Formal Structures for Computation and Deduction (FSCD 2026)

Abstract
The axiom of choice (AC) states that every total relation contains a function. It enjoys a pivotal role in both classical and constructive dialects of mathematics. In the former, it is seen as a useful closure property invoked especially in set-theoretic contexts, in the latter it is seen either as a tautology, following from a constructive reading of totality proofs, or as a taboo, as by an extensional reading of totality proofs it enforces full classical logic. It has therefore been debated how much of AC should be accepted in constructive foundations and authors like Richman argued for "Constructive mathematics without choice" where even countable choice, not immediately jeopardising constructive reasoning, is avoided. With this paper, we propose a continuation of Richman’s programme of more radical extent and systematically study constructive foundations absent of countable, unique, or quantifier-free choice principles as well as the spurious fragments of (the actual) AC in form of extensionality principles: "Constructive mathematics without any choice" We argue that such a minimalistic setting is advantageous, for instance for studies in constructive reverse mathematics and synthetic computability theory. Apart from these programmatic considerations and a careful encyclopedia of choice principles, we revisit and refine several results from the literature: We show that already the partition principle (a consequence of AC of unknown strength) implies the excluded middle, that already logically decidable (inductive) equality of propositions implies proof irrelevance, and that function inversion principles such as the Cantor-Bernstein theorem not only rely on the excluded middle but also on unique choice. To the best of our knowledge, the latter is the first reverse mathematics result regarding the full axiom of unique choice, enabled by our minimal setting. Implementing such a minimalistic foundation, the proofs of all our results have been mechanised with the Rocq prover.
Cite as

Martin Baillon, Yannick Forster, Dominik Kirst, Assia Mahboubi, and Pierre-Marie Pédrot. Not Choosing Is Still a Choice: Constructive mathematics without any choice. In 11th International Conference on Formal Structures for Computation and Deduction (FSCD 2026). Leibniz International Proceedings in Informatics (LIPIcs), Volume 378, pp. 5:1-5:23, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2026)

Copy BibTex To Clipboard

@InProceedings{baillon_et_al:LIPIcs.FSCD.2026.5,
  author =	{Baillon, Martin and Forster, Yannick and Kirst, Dominik and Mahboubi, Assia and P\'{e}drot, Pierre-Marie},
  title =	{{Not Choosing Is Still a Choice: Constructive mathematics without any choice}},
  booktitle =	{11th International Conference on Formal Structures for Computation and Deduction (FSCD 2026)},
  pages =	{5:1--5:23},
  series =	{Leibniz International Proceedings in Informatics (LIPIcs)},
  ISBN =	{978-3-95977-433-8},
  ISSN =	{1868-8969},
  year =	{2026},
  volume =	{378},
  editor =	{Pfenning, Frank},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops.dagstuhl.de/entities/document/10.4230/LIPIcs.FSCD.2026.5},
  URN =		{urn:nbn:de:0030-drops-263553},
  doi =		{10.4230/LIPIcs.FSCD.2026.5},
  annote =	{Keywords: Axiom of Choice, Constructive Mathematics, Type Theory}
}
Document
DOI: 10.4230/LIPIcs.FSCD.2025.9
A Zoo of Continuity Properties in Constructive Type Theory

Authors: Martin Baillon, Yannick Forster, Assia Mahboubi, Pierre-Marie Pédrot, and Matthieu Piquerez

Published in: LIPIcs, Volume 337, 10th International Conference on Formal Structures for Computation and Deduction (FSCD 2025)

Abstract
Continuity principles stating that all functions are continuous play a central role in some schools of constructive mathematics. However, there are different ways to formalise the property of being continuous in constructive foundations. We analyse these continuity properties from the perspective of constructive reverse mathematics. We work in constructive type theory, which can be seen as a minimal foundation for constructive reverse mathematics. We treat continuity of functions F : (Q → A) → R, i.e. with question type Q, answer type A, and result type R. Concretely, we discuss continuity defined via moduli, making the relevant list L : LQ of questions explicit, dialogue trees, making the question-answer process explicit as inductive tree, and tree functions, making the question-answer process explicit as function. We prove equivalences where possible and isolate necessary and sufficient axioms for equivalence proofs. Many of the results we discuss are already present in the works of Hancock, Pattinson, Ghani, Kawai, Fujiwara, Brede, Herbelin, Escardó, and others. Our main contribution is their formulation over a uniform foundation, the observation that no choice axioms are necessary, the generalisation to arbitrary types from natural numbers where possible, and a mechanisation in the Coq/Rocq proof assistant.
Cite as

Martin Baillon, Yannick Forster, Assia Mahboubi, Pierre-Marie Pédrot, and Matthieu Piquerez. A Zoo of Continuity Properties in Constructive Type Theory. In 10th International Conference on Formal Structures for Computation and Deduction (FSCD 2025). Leibniz International Proceedings in Informatics (LIPIcs), Volume 337, pp. 9:1-9:20, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2025)

Copy BibTex To Clipboard

@InProceedings{baillon_et_al:LIPIcs.FSCD.2025.9,
  author =	{Baillon, Martin and Forster, Yannick and Mahboubi, Assia and P\'{e}drot, Pierre-Marie and Piquerez, Matthieu},
  title =	{{A Zoo of Continuity Properties in Constructive Type Theory}},
  booktitle =	{10th International Conference on Formal Structures for Computation and Deduction (FSCD 2025)},
  pages =	{9:1--9:20},
  series =	{Leibniz International Proceedings in Informatics (LIPIcs)},
  ISBN =	{978-3-95977-374-4},
  ISSN =	{1868-8969},
  year =	{2025},
  volume =	{337},
  editor =	{Fern\'{a}ndez, Maribel},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops.dagstuhl.de/entities/document/10.4230/LIPIcs.FSCD.2025.9},
  URN =		{urn:nbn:de:0030-drops-236245},
  doi =		{10.4230/LIPIcs.FSCD.2025.9},
  annote =	{Keywords: type theory, constructive mathematics, continuity, Coq}
}
Document
Complete Volume
DOI: 10.4230/LIPIcs.TYPES.2022
LIPIcs, Volume 269, TYPES 2022, Complete Volume

Authors: Delia Kesner and Pierre-Marie Pédrot

Published in: LIPIcs, Volume 269, 28th International Conference on Types for Proofs and Programs (TYPES 2022)

Abstract
LIPIcs, Volume 269, TYPES 2022, Complete Volume
Cite as

28th International Conference on Types for Proofs and Programs (TYPES 2022). Leibniz International Proceedings in Informatics (LIPIcs), Volume 269, pp. 1-342, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2023)

Copy BibTex To Clipboard

@Proceedings{kesner_et_al:LIPIcs.TYPES.2022,
  title =	{{LIPIcs, Volume 269, TYPES 2022, Complete Volume}},
  booktitle =	{28th International Conference on Types for Proofs and Programs (TYPES 2022)},
  pages =	{1--342},
  series =	{Leibniz International Proceedings in Informatics (LIPIcs)},
  ISBN =	{978-3-95977-285-3},
  ISSN =	{1868-8969},
  year =	{2023},
  volume =	{269},
  editor =	{Kesner, Delia and P\'{e}drot, Pierre-Marie},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops.dagstuhl.de/entities/document/10.4230/LIPIcs.TYPES.2022},
  URN =		{urn:nbn:de:0030-drops-184425},
  doi =		{10.4230/LIPIcs.TYPES.2022},
  annote =	{Keywords: LIPIcs, Volume 269, TYPES 2022, Complete Volume}
}
Document
Front Matter
DOI: 10.4230/LIPIcs.TYPES.2022.0
Front Matter, Table of Contents, Preface, Conference Organization

Authors: Delia Kesner and Pierre-Marie Pédrot

Published in: LIPIcs, Volume 269, 28th International Conference on Types for Proofs and Programs (TYPES 2022)

Abstract
Front Matter, Table of Contents, Preface, Conference Organization
Cite as

28th International Conference on Types for Proofs and Programs (TYPES 2022). Leibniz International Proceedings in Informatics (LIPIcs), Volume 269, pp. 0:i-0:viii, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2023)

Copy BibTex To Clipboard

@InProceedings{kesner_et_al:LIPIcs.TYPES.2022.0,
  author =	{Kesner, Delia and P\'{e}drot, Pierre-Marie},
  title =	{{Front Matter, Table of Contents, Preface, Conference Organization}},
  booktitle =	{28th International Conference on Types for Proofs and Programs (TYPES 2022)},
  pages =	{0:i--0:viii},
  series =	{Leibniz International Proceedings in Informatics (LIPIcs)},
  ISBN =	{978-3-95977-285-3},
  ISSN =	{1868-8969},
  year =	{2023},
  volume =	{269},
  editor =	{Kesner, Delia and P\'{e}drot, Pierre-Marie},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops.dagstuhl.de/entities/document/10.4230/LIPIcs.TYPES.2022.0},
  URN =		{urn:nbn:de:0030-drops-184433},
  doi =		{10.4230/LIPIcs.TYPES.2022.0},
  annote =	{Keywords: Front Matter, Table of Contents, Preface, Conference Organization}
}
Document
DOI: 10.4230/LIPIcs.CSL.2022.5
Gardening with the Pythia A Model of Continuity in a Dependent Setting

Authors: Martin Baillon, Assia Mahboubi, and Pierre-Marie Pédrot

Published in: LIPIcs, Volume 216, 30th EACSL Annual Conference on Computer Science Logic (CSL 2022)

Abstract
We generalize to a rich dependent type theory a proof originally developed by Escardó that all System 𝚃 functionals are continuous. It relies on the definition of a syntactic model of Baclofen Type Theory, a type theory where dependent elimination must be strict, into the Calculus of Inductive Constructions. The model is given by three translations: the axiom translation, that adds an oracle to the context; the branching translation, based on the dialogue monad, turning every type into a tree; and finally, a layer of algebraic binary parametricity, binding together the two translations. In the resulting type theory, every function f : (ℕ → ℕ) → ℕ is externally continuous.
Cite as

Martin Baillon, Assia Mahboubi, and Pierre-Marie Pédrot. Gardening with the Pythia A Model of Continuity in a Dependent Setting. In 30th EACSL Annual Conference on Computer Science Logic (CSL 2022). Leibniz International Proceedings in Informatics (LIPIcs), Volume 216, pp. 5:1-5:18, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2022)

Copy BibTex To Clipboard

@InProceedings{baillon_et_al:LIPIcs.CSL.2022.5,
  author =	{Baillon, Martin and Mahboubi, Assia and P\'{e}drot, Pierre-Marie},
  title =	{{Gardening with the Pythia A Model of Continuity in a Dependent Setting}},
  booktitle =	{30th EACSL Annual Conference on Computer Science Logic (CSL 2022)},
  pages =	{5:1--5:18},
  series =	{Leibniz International Proceedings in Informatics (LIPIcs)},
  ISBN =	{978-3-95977-218-1},
  ISSN =	{1868-8969},
  year =	{2022},
  volume =	{216},
  editor =	{Manea, Florin and Simpson, Alex},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops.dagstuhl.de/entities/document/10.4230/LIPIcs.CSL.2022.5},
  URN =		{urn:nbn:de:0030-drops-157256},
  doi =		{10.4230/LIPIcs.CSL.2022.5},
  annote =	{Keywords: Type theory, continuity, syntactic model}
}
Any Issues?
X

Feedback on the Current Page

CAPTCHA

Thanks for your feedback!

Feedback submitted to Dagstuhl Publishing

Could not send message

Please try again later or send an E-mail
© 2023-2026 Schloss Dagstuhl – LZI GmbH Schloss Dagstuhl – LZI GmbH About DROPS Imprint Privacy Contact