On a model invariance problem in Homotopy Type Theory
Abstract
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 type theory with dependent sums, dependent products, identity types and a univalent universe. This model, together with the model (developed by the author in an other work) in the same underlying category together with the very same universe that turned out to be provably not univalent with respect to projective fibrations, provides an example of two Quillen equivalent model categories that host different models of type theory. Thus, we provide a counterexample to the model invariance problem formulated by Michael Shulman.
Cite
@article{arxiv.1712.03409,
title = {On a model invariance problem in Homotopy Type Theory},
author = {Anthony Bordg},
journal= {arXiv preprint arXiv:1712.03409},
year = {2017}
}
Comments
11 pages. This text partly overlaps arXiv:1512.04083, but it is entirely rewritten and self-contained