arXiv Machine Learning By Xiaoyu Li, Zhizhou Sha, Chiwun Yang, Dai Shi

A Categorical Atlas of Parameter-Efficient Fine-Tuning: Cones, Orbits, and Gauges

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The paper presents a comprehensive framework for comparing parameter‑efficient fine‑tuning (PEFT) methods by treating each as a smooth map from a small parameter space into weight space, with a pretrained checkpoint as the base point. It identifies three key invariants—image near the base point, fibre dynamics, and base change—that explain expressivity, training dynamics, and initialization behavior. The authors prove numerous results about common PEFT techniques (e.g., LoRA, Householder adaptation) and classify 382 methods from 138 papers using seven coordinate descriptors.

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