Ph.D. Candidate: Ian Helfrich

Dissertation Title:  The Economic Geometry of Trade: Synthesizing Networks, Geospatial Analytics, and Optimal Transport

Dissertation Abstract: 

This dissertation explores international trade through three distinct perspectives. The first paper introduces a time-varying, directional, and scale-agnostic measure of economic distance in trade models. Using remote sensing and GIS techniques, distance is defined based on population-weighted and nighttime lights-weighted centroids. This method captures micro-level economic and environmental conditions, reflected through shifts in spatial distribution of populations and economic activity, and allows for the calculation of distance fixed effects in panel models. 

The second paper integrates network centrality measures into a structural gravity model, highlighting the role of a country's network position in shaping trade relationships. By constructing multilevel trade networks from BACI bilateral trade data (CEPII) and incorporating structural gravity covariates, a global network centrality dataset is derived. Low-dimensional interactions are analyzed using tensor decomposition and t-SNE, revealing latent dependencies within the trade network. These measures are then included as explanatory variables in the gravity model, estimated using the Pseudo-Poisson Maximum Likelihood (PPML) estimator. 

The third chapter proposes a general economic equilibrium framework using optimal transport within infinite-dimensional Hilbert spaces. The existence and uniqueness of equilibrium are proven, characterizing equilibrium allocations as solutions to an optimal transport problem. Tools from functional analysis and convex optimization are used to study the efficiency and fairness properties of equilibrium allocations across various economic settings.

This dissertation offers interdisciplinary perspectives on global trade dynamics by synthesizing insights from network theory, spatial econometrics, and functional analysis, providing a foundation for future research

Committee:

Usha Nair-Reichert (Co-Advisor), Associate Professor, Georgia Institute of Technology

Tibor Besedes (Co-Advisor), Mary S. and Richard B. Inman, Jr. Professor of Economics, Georgia Institute of Technology

Maxwell Rosenthal, Assistant Professor, Georgia Institute of Technology

Casey Wichman, Associate Professor, Georgia Institute of Technology

David Anderson (external member), Professor, School of Electrical and Computer Engineering, Georgia Institute of Technology

Date: July 15, 2024

Time: 12:00 pm – 2:15 pm EDT

Location: Virtual (Zoom Link)

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Zoom is the leader in modern enterprise video communications, with an easy, reliable cloud platform for video and audio conferencing, chat, and webinars across mobile, desktop, and room systems. Zoom Rooms is the original software-based conference room solution used around the world in board, conference, huddle, and training rooms, as well as executive offices and classrooms. Founded in 2011, Zoom helps businesses and organizations bring their teams together in a frictionless environment to get more done. Zoom is a publicly traded company headquartered in San Jose, CA.

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