arXiv subjects

Joshua Chen

Publications and source records attributed to Joshua Chen.

22 records · Page 2Linked to original sources

arXiv2021

Homotopy Type Theory in Isabelle

This paper introduces Isabelle/HoTT, the first development of homotopy type theory in the Isabelle proof assistant. Building on earlier work by Paulson, I use Isabelle's existing logical framework infrastructure to implement essential automation, such as type checking and term elaboration, that is usually handled on the source code level of dependently typed systems. I also integrate the propositions-as-types paradigm with the declarative Isar proof language, providing an alternative to the tactic-based proofs of Coq and the proof terms of Agda. The infrastructure developed is then used to formalize foundational results from the Homotopy Type Theory book.

cs.LO↗

arXiv2020

Projected Stein Variational Newton: A Fast and Scalable Bayesian Inference Method in High Dimensions

We propose a fast and scalable variational method for Bayesian inference in high-dimensional parameter space, which we call projected Stein variational Newton (pSVN) method. We exploit the intrinsic low-dimensional geometric structure of the posterior distribution in the high-dimensional parameter space via its Hessian (of the log posterior) operator and perform a parallel update of the parameter samples projected into a low-dimensional subspace by an SVN method. The subspace is adaptively constructed using the eigenvectors of the averaged Hessian at the current samples. We demonstrate fast convergence of the proposed method and its scalability with respect to the number of parameters, samples, and processor cores.

math.OC↗

arXiv2019

An Implementation of Homotopy Type Theory in Isabelle/Pure

In this Masters thesis we present an implementation of a fragment of "book HoTT" as an object logic for the interactive proof assistant Isabelle. We also give a mathematical description of the underlying theory of the Isabelle/Pure logical framework, and discuss various issues and design decisions that arise when attempting to encode intensional dependent type theory with universes inside a simple type-theoretic logical foundation.

cs.LO↗

arXiv2014

The Temperley-Lieb categories and skein modules

We develop the theory of diagrammatic Temperley-Lieb categories in order to construct examples of spherical fusion categories, which we then use to construct Turaev-Viro skein modules for n-holed disks. This is a thesis submitted for the degree of Bachelor of Science with Honours at the Australian National University.

math.QA↗