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Main Authors: Kawata, Ryotaro, Matsutani, Kohsei, Kinoshita, Yuri, Nishikawa, Naoki, Suzuki, Taiji
Format: Preprint
Published: 2025
Subjects:
Online Access:https://arxiv.org/abs/2506.01656
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author Kawata, Ryotaro
Matsutani, Kohsei
Kinoshita, Yuri
Nishikawa, Naoki
Suzuki, Taiji
author_facet Kawata, Ryotaro
Matsutani, Kohsei
Kinoshita, Yuri
Nishikawa, Naoki
Suzuki, Taiji
contents Mixture of Experts (MoE), an ensemble of specialized models equipped with a router that dynamically distributes each input to appropriate experts, has achieved successful results in the field of machine learning. However, theoretical understanding of this architecture is falling behind due to its inherent complexity. In this paper, we theoretically study the sample and runtime complexity of MoE following the stochastic gradient descent (SGD) when learning a regression task with an underlying cluster structure of single index models. On the one hand, we prove that a vanilla neural network fails in detecting such a latent organization as it can only process the problem as a whole. This is intrinsically related to the concept of information exponent which is low for each cluster, but increases when we consider the entire task. On the other hand, we show that a MoE succeeds in dividing this problem into easier subproblems by leveraging the ability of each expert to weakly recover the simpler function corresponding to an individual cluster. To the best of our knowledge, this work is among the first to explore the benefits of the MoE framework by examining its SGD dynamics in the context of nonlinear regression.
format Preprint
id arxiv_https___arxiv_org_abs_2506_01656
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Mixture of Experts Provably Detect and Learn the Latent Cluster Structure in Gradient-Based Learning
Kawata, Ryotaro
Matsutani, Kohsei
Kinoshita, Yuri
Nishikawa, Naoki
Suzuki, Taiji
Machine Learning
Mixture of Experts (MoE), an ensemble of specialized models equipped with a router that dynamically distributes each input to appropriate experts, has achieved successful results in the field of machine learning. However, theoretical understanding of this architecture is falling behind due to its inherent complexity. In this paper, we theoretically study the sample and runtime complexity of MoE following the stochastic gradient descent (SGD) when learning a regression task with an underlying cluster structure of single index models. On the one hand, we prove that a vanilla neural network fails in detecting such a latent organization as it can only process the problem as a whole. This is intrinsically related to the concept of information exponent which is low for each cluster, but increases when we consider the entire task. On the other hand, we show that a MoE succeeds in dividing this problem into easier subproblems by leveraging the ability of each expert to weakly recover the simpler function corresponding to an individual cluster. To the best of our knowledge, this work is among the first to explore the benefits of the MoE framework by examining its SGD dynamics in the context of nonlinear regression.
title Mixture of Experts Provably Detect and Learn the Latent Cluster Structure in Gradient-Based Learning
topic Machine Learning
url https://arxiv.org/abs/2506.01656