Learning Linear Regression with Low-Rank Tasks in-Context
- URL: http://arxiv.org/abs/2510.04548v1
- Date: Mon, 06 Oct 2025 07:27:49 GMT
- Title: Learning Linear Regression with Low-Rank Tasks in-Context
- Authors: Kaito Takanami, Takashi Takahashi, Yoshiyuki Kabashima,
- Abstract summary: In-context learning (ICL) is a key building block of modern large language models.<n>We analyze a linear attention model trained on low-rank regression tasks.<n>We find that statistical fluctuations in finite pre-training data induce an implicit regularization.
- Score: 8.347662730632047
- License: http://creativecommons.org/licenses/by/4.0/
- Abstract: In-context learning (ICL) is a key building block of modern large language models, yet its theoretical mechanisms remain poorly understood. It is particularly mysterious how ICL operates in real-world applications where tasks have a common structure. In this work, we address this problem by analyzing a linear attention model trained on low-rank regression tasks. Within this setting, we precisely characterize the distribution of predictions and the generalization error in the high-dimensional limit. Moreover, we find that statistical fluctuations in finite pre-training data induce an implicit regularization. Finally, we identify a sharp phase transition of the generalization error governed by task structure. These results provide a framework for understanding how transformers learn to learn the task structure.
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