An Efficient Stochastic First-Order Algorithm for Nonconvex-Strongly Concave Minimax Optimization beyond Lipschitz Smoothness

Fuente: arXiv
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Main Authors: Gao, Yan, Liu, Yongchao
Format: Preprint
Published: 2026
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author Gao, Yan
Liu, Yongchao
author_facet Gao, Yan
Liu, Yongchao
contents In recent years, nonconvex minimax problems have attracted significant attention due to their broad applications in machine learning, including generative adversarial networks, robust optimization and adversarial training. Most existing algorithms for nonconvex stochastic minimax problems are developed under the standard Lipschitz smoothness assumption. In this paper, we study stochastic minimax problems under a generalized smoothness condition and propose an algorithm, NSGDA-M, which simultaneously updates the inner variable by stochastic gradient ascent and updates the outer variable by normalized stochastic gradient descent with momentum. When the objective function is nonconvex-strongly concave, we show that NSGDA-M finds an $ε$-stationary point of the primal function within $\mathcal{O}(ε^{-4})$ stochastic gradient evaluations in expectation, and $\mathcal{O}\left(ε^{-4}(\log(\frac{1}δ))^{3/2}\right)$ stochastic gradient evaluations in high probability, where $δ\in (0,1)$ is the failure probability. We verify the effectiveness of the proposed algorithm through numerical experiments on a distributionally robust optimization problem.
format Preprint
id arxiv_https___arxiv_org_abs_2603_04940
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle An Efficient Stochastic First-Order Algorithm for Nonconvex-Strongly Concave Minimax Optimization beyond Lipschitz Smoothness
Gao, Yan
Liu, Yongchao
Optimization and Control
90C26, 49M37, 68Q25
In recent years, nonconvex minimax problems have attracted significant attention due to their broad applications in machine learning, including generative adversarial networks, robust optimization and adversarial training. Most existing algorithms for nonconvex stochastic minimax problems are developed under the standard Lipschitz smoothness assumption. In this paper, we study stochastic minimax problems under a generalized smoothness condition and propose an algorithm, NSGDA-M, which simultaneously updates the inner variable by stochastic gradient ascent and updates the outer variable by normalized stochastic gradient descent with momentum. When the objective function is nonconvex-strongly concave, we show that NSGDA-M finds an $ε$-stationary point of the primal function within $\mathcal{O}(ε^{-4})$ stochastic gradient evaluations in expectation, and $\mathcal{O}\left(ε^{-4}(\log(\frac{1}δ))^{3/2}\right)$ stochastic gradient evaluations in high probability, where $δ\in (0,1)$ is the failure probability. We verify the effectiveness of the proposed algorithm through numerical experiments on a distributionally robust optimization problem.
title An Efficient Stochastic First-Order Algorithm for Nonconvex-Strongly Concave Minimax Optimization beyond Lipschitz Smoothness
topic Optimization and Control
90C26, 49M37, 68Q25
url https://arxiv.org/abs/2603.04940