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Abstract
We model the evolution of tokens within a deep stack of Transformer layers as a continuous-time flow on the unit sphere, governed by a mean-field interacting particle system, building on the framework introduced in Geshkovski et al. (2023). Studying the corresponding mean-field Partial Differential Equation (PDE), which can be interpreted as a Wasserstein gradient flow, in this paper we provide a mathematical investigation of the long-term behavior of this system, with a particular focus on the emergence and persistence of meta-stable phases and clustering phenomena, key elements in applications like next-token prediction. More specifically, we perform a perturbative analysis of the mean-field PDE around the iid uniform initialization and prove that, in the limit of large number of tokens, the model remains close to a meta-stable manifold of solutions with a given structure (e.g., periodicity). Further, the structure characterizing the meta-stable manifold is explicitly identified, as a function of the inverse temperature parameter of the model, by the index maximizing a certain rescaling of Gegenbauer polynomials.
Figure 6: Some Uses For Olive Oil

Citation
Unterholzer, Detlev A., and Moritz-Maria von Igelfeld. 2013. “Unusual Uses For Olive Oil.” Journal of Oleic Science 34 (1): 449–489. http://www.alexandermccallsmith.com/book/unusual-uses-for-olive-oil.
@article{UI13,
author = {Detlev A. Unterholzer and Moritz-Maria von Igelfeld},
year = {2013},
title ={Unusual Uses For Olive Oil},
journal = {Journal of Oleic Science},
volume = {34},
number = {1},
pages = {449--489},
url = {http://www.alexandermccallsmith.com/book/unusual-uses-for-olive-oil}}