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Louis Goldwater Christie

Department of Data Science and Operations, University of Southern California
lgchrist (at) usc (dot) edu
github.com/lchristie
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CV

Research Interests

I focus on data that lives in complex nonlinear spaces: how can we build estimation and inferential methods when we lose our usual intuitions about means and variances. This relies on understanding the geometry of the space that our data lives in so that we can construct tools that work intrinsically for these dataspaces.

I am currently working with Oceanographic data, in particular modelling a time series of cell size distributions via stochastic transport maps. This expands on existing Wasserstein space time series to allow for the random behaviour of the physical cells. I am interested in missing data problems and am working on better methods to incorporate incompletely sequenced genomes into estimates of community gene prevalence.

I also work on dimension reduction techniques, including generalising notions of sparsity to achieve adaptive non-linear dimension reduction in non-parametric regression problems. This comes from studying symmetries of the underlying regression function. This work has applications in diverse scientific fields, including examining the behaviour of sunspots and in protein imaging tools such as Cryo-Electron Microscopy. I am very interested in further developments in the theory of symmetry discovery, particularly in statistical-computational gaps and in robustness problems.

Academic History

Since September 2025, I have been a Postdoctoral Scholar at the University of Southern California in Prof. Jacob Bien's group. This position is part of the CBIOMES Simons Foundation Collaboration. Before this I was a Postdoctoral research assistant at the University of Cambridge in the Statistical Laboratory continuing to work with my PhD advisor, Prof. Sir John Aston. I was a Harding Distinguished Postgraduate Scholar during my PhD at Cambridge, and I graduated there in October 2024 with a thesis titled "Symmetry and Other Structures: Topics in Nonparametric Regression". During my PhD, I won the Smith-Knight prize in the department for part of the work that went into my thesis. I also completed a Masters degree in Mathematical Statistics from Cambridge (Part III Mathematics) and conjoint degrees in Mathematics, Statistics, Economics and Physics from the University of Auckland with First Class Honours.

Personal Information

Outside of statistics, I enjoy mountaineering and skiing, playing squash and tennis, and cycle touring.

Gokyo Valley, Nepal Mt. Tremblant Skiing, Canada Vodnikov Dom and Triglav, Slovenia Under the Garden of Eden, NZ