Learning Spectral Methods by Transformers

Fuente: arXiv
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Auteurs principaux: He, Yihan, Cao, Yuan, Chen, Hong-Yu, Wu, Dennis, Fan, Jianqing, Liu, Han
Format: Preprint
Publié: 2025
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author He, Yihan
Cao, Yuan
Chen, Hong-Yu
Wu, Dennis
Fan, Jianqing
Liu, Han
author_facet He, Yihan
Cao, Yuan
Chen, Hong-Yu
Wu, Dennis
Fan, Jianqing
Liu, Han
contents Transformers demonstrate significant advantages as the building block of modern LLMs. In this work, we study the capacities of Transformers in performing unsupervised learning. We show that multi-layered Transformers, given a sufficiently large set of pre-training instances, are able to learn the algorithms themselves and perform statistical estimation tasks given new instances. This learning paradigm is distinct from the in-context learning setup and is similar to the learning procedure of human brains where skills are learned through past experience. Theoretically, we prove that pre-trained Transformers can learn the spectral methods and use the classification of bi-class Gaussian mixture model as an example. Our proof is constructive using algorithmic design techniques. Our results are built upon the similarities of multi-layered Transformer architecture with the iterative recovery algorithms used in practice. Empirically, we verify the strong capacity of the multi-layered (pre-trained) Transformer on unsupervised learning through the lens of both the PCA and the Clustering tasks performed on the synthetic and real-world datasets.
format Preprint
id arxiv_https___arxiv_org_abs_2501_01312
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Learning Spectral Methods by Transformers
He, Yihan
Cao, Yuan
Chen, Hong-Yu
Wu, Dennis
Fan, Jianqing
Liu, Han
Machine Learning
Statistics Theory
Transformers demonstrate significant advantages as the building block of modern LLMs. In this work, we study the capacities of Transformers in performing unsupervised learning. We show that multi-layered Transformers, given a sufficiently large set of pre-training instances, are able to learn the algorithms themselves and perform statistical estimation tasks given new instances. This learning paradigm is distinct from the in-context learning setup and is similar to the learning procedure of human brains where skills are learned through past experience. Theoretically, we prove that pre-trained Transformers can learn the spectral methods and use the classification of bi-class Gaussian mixture model as an example. Our proof is constructive using algorithmic design techniques. Our results are built upon the similarities of multi-layered Transformer architecture with the iterative recovery algorithms used in practice. Empirically, we verify the strong capacity of the multi-layered (pre-trained) Transformer on unsupervised learning through the lens of both the PCA and the Clustering tasks performed on the synthetic and real-world datasets.
title Learning Spectral Methods by Transformers
topic Machine Learning
Statistics Theory
url https://arxiv.org/abs/2501.01312