[CS] Christopher Wolfram MS Presentation/Jul 29, 2025

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This is an announcement of Christopher Wolfram's MS Presentation
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Candidate: Christopher Wolfram

Date: Tuesday, July 29, 2025

Time:  1 pm CST

Remote Location: https://uchicago.zoom.us/j/95012543768?pwd=bbtjxmgsKS9W6U2bHtBIO4uB6lGgPa.1  Meeting ID: 950 1254 3768 Passcode: 392999

Location: JCL 298

Title: Layers at Similar Depths Generate Similar Activations Across LLM Architectures

Abstract: How do the latent spaces used by independently-trained LLMs relate to one another? We study the nearest neighbor relationships induced by activations at different layers of 24 open-weight LLMs, and find that they 1) tend to vary from layer to layer within a model, and 2) are approximately shared between corresponding layers of different models. Claim 2 shows that these nearest neighbor relationships are not arbitrary, as they are shared across models, but Claim 1 shows that they are not "obvious" either, as there is no single set of nearest neighbor relationships that is universally shared. Together, these suggest that LLMs generate a progression of activation geometries from layer to layer, but that this entire progression is largely shared between models, stretched and squeezed to fit into different architectures.

Advisors: Aaron Schein

Committee Members: Aaron Schein, Ari Holtzman, and Chenhao Tan