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Defeng Sun

5 accepted papers

2026

Approximation Bounds for Transformer Networks with Application to Regression

ICML 2026poster

We develop approximation and statistical theory for standard Transformer networks in sequence modeling. Given a sequence-to-sequence target on $[0,1]^{d_x \times n}$ whose entries are $\gamma$-H\"older for $\gamma \in (0,1]$ or belong to a first-order Sobolev class, we establish explicit $L^p$-appro…

Cited by 0SourceScholar
2025

A Tight Convergence Analysis of Inexact Stochastic Proximal Point Algorithm for Stochastic Composite Optimization Problems

ICLR 2025poster

The \textbf{i}nexact \textbf{s}tochastic \textbf{p}roximal \textbf{p}oint \textbf{a}lgorithm (isPPA) is popular for solving stochastic composite optimization problems with many applications in machine learning. While the convergence theory of the (inexact) PPA has been well established, the known co…

Cited by 0SourcePDFScholar
2024

Globally Q-linear Gauss-Newton Method for Overparameterized Non-convex Matrix Sensing

NeurIPS 2024poster

This paper focuses on the optimization of overparameterized, non-convex low-rank matrix sensing (LRMS)—an essential component in contemporary statistics and machine learning. Recent years have witnessed significant breakthroughs in first-order methods, such as gradient descent, for tackling this non…

2023

Beyond ADMM: A Unified Client-Variance-Reduced Adaptive Federated Learning Framework

AAAI 2023technical

As a novel distributed learning paradigm, federated learning (FL) faces serious challenges in dealing with massive clients with heterogeneous data distribution and computation and communication resources. Various client-variance-reduction schemes and client sampling strategies have been respectively…

Cited by 12SourcePDFScholar