arXiv AI

Optimal Transport Aggregation for Distributed Mixture-of-Experts

The paper addresses how to combine independently fitted local Mixture-of-Experts (MoE) models from distributed datasets into a single global MoE. It proposes reducing the resulting large mixture to a K‑expert model by minimizing an expected transportation divergence that depends on covariates, using a majorization–minimization algorithm for experts and a separate fitting for the gating network. The method guarantees consistency of the aggregated estimator, requires only one one‑way communication round, and achieves accuracy close to centralized estimation while cutting computation time.

arXiv Machine Learning
Sep 4

Towards a Statistical Understanding of Mixture-of-Experts

The paper presents a statistical framework for Mixture-of-Experts (MoE) models, treating them as localized aggregation systems. It derives oracle risk bounds that separate approximation, expert‑learning, and router‑estimation errors for both dense and sparse routing with evolving experts. The authors also analyze how sparse Top‑K routing balances computational cost with performance, interpret gating geometrically, and explain how shared experts can capture common predictive structure while allowing routed experts to focus on local residuals.

By Siyuan He, Bokai Yang, Jie Hu, Ziwen Gao, Yuhong Yang
arXiv Machine Learning
Oct 22

Generalization and Scaling Laws for Mixture-of-Experts Transformers

The paper presents a theoretical framework for understanding generalization and scaling in Mixture-of-Experts (MoE) Transformers. It derives a sup‑norm covering‑number bound that separates active per‑input capacity from routing combinatorics, leading to a generalization bound under a manifold data model. Additionally, a constructive approximation theorem shows how error can be reduced by scaling active capacity or increasing the number of experts, from which neural scaling laws and compute‑optimal tradeoffs are derived.

By Mansour Zoubeirou a Mayaki
arXiv Machine Learning
Oct 9

Smoothing the Top-k Exposure Boundary for Sparse Mixture-of-Experts

The paper introduces Elastic Expert Routing, a method that replaces the fixed top‑k expert selection in Sparse Mixture‑of‑Experts models with a stochastic sampling of the expert budget around k. This approach smooths the hard boundary between fully supervised and zero‑feedback experts, maintaining the same expected compute cost while improving training stability. Experiments show that elastic routing boosts downstream performance on supervised fine‑tuning and from‑scratch pretraining, achieving higher macro‑averages on OLMoE‑1B‑7B, Qwen3‑30B‑A3B, and outperforming static top‑k baselines by an average of 1.6 points.

By Yunkai Chai, Tong Zhu, Xiaoye Qu, Xuyang Hu, Guanjie Chen, Qipeng Guo, Yu Cheng
arXiv AI
Aug 11

UniMoMo: Expert Merging-Based MoE Acceleration for Large Recommendation Models

arXiv:2608. 08627v1 Announce Type: new Abstract: Sparse mixture-of-experts (MoE) layers expand recommendation capacity through conditional computation, yet a trained checkpoint still stores and routes over its full expert bank.

By Lei Xin, Bin Gu, Peize Li, Zitong Wang, Jianbo Zhao, Changjiang Jiang, Yanyue Xie, Chao Huang, Xuyang Zhao, Zunhai Su, Fanhu Zeng, Zhenglun Kong
arXiv Machine Learning
Oct 3

Redundancy Meets Synergy: Dependency-aware Expert Selection for MoE via Submodular Optimization

The paper introduces DS-MoE, a framework that selects a compact subset of experts in Mixture-of-Experts models using difference-of-submodular (DS) optimization. It analyzes the loss degradation via a second-order Taylor expansion to uncover redundancy and synergy among experts, and formulates the selection objective to decouple these effects. A majorization-minimization algorithm with monotonicity guarantees efficiently identifies the optimal subset, and experiments show DS-MoE outperforms state‑of‑the‑art baselines.

By Zheng Lin, Shaoke Fang, Yuxin Zhang, Jinfeng Xu, Zihan Fang, Zhe Chen, Wei Ni, Jun Luo, Symeon Chatzinotas