Abstract
In the first part of this paper we present a formalization in Agda of the James construction in homotopy type theory. We include several fragments of code to show what the Agda code looks like, and we explain several techniques that we used in the formalization. In the second part, we use the James construction to give a constructive proof that \(\pi _4(\mathbb {S}^{3})\) is of the form \(\mathbb {Z}/n\mathbb {Z}\) (but we do not compute the n here).
Similar content being viewed by others
Notes
The code is available at https://github.com/guillaumebrunerie/JamesConstruction and has been tested with Agda 2.5.2. The code fragments are generated directly from the source code using agda --latex and a custom script to extract the relevant parts.
References
Brunerie, G.: On the homotopy groups of spheres in homotopy type theory. PhD thesis (2016). arxiv:1606.05916
Cockx, J., Abel, A.: Sprinkles of extensionality for your vanilla type theory. TYPES (2016). http://www.types2016.uns.ac.rs/images/abstracts/cockx.pdf
Hou, K.-B., Finster, E., Licata, D.R., Lumsdaine, P.L.: A mechanization of the Blakers-Massey connectivity theorem in homotopy type theory. LICS (2016). https://doi.org/10.1145/2933575.2934545
Licata, D.R., Brunerie, G.: A cubical approach to synthetic homotopy theory. LICS (2015). https://doi.org/10.1109/LICS.2015.19
The Univalent Foundations Program: Homotopy Type Theory: Univalent Foundations of Mathematics. Institute for Advanced Study, Princeton, NJ (2013). http://homotopytypetheory.org/book
Author information
Authors and Affiliations
Corresponding author
Additional information
This material is based upon work supported by the National Science Foundation under Agreement Nos. DMS-1128155 and CMU 1150129-338510.
Rights and permissions
About this article
Cite this article
Brunerie, G. The James Construction and \(\pi _4(\mathbb {S}^{3})\) in Homotopy Type Theory. J Autom Reasoning 63, 255–284 (2019). https://doi.org/10.1007/s10817-018-9468-2
Received:
Accepted:
Published:
Issue Date:
DOI: https://doi.org/10.1007/s10817-018-9468-2