2021/04/18 by Haochuan Li, Li, Haochuan, Yi Tian +5 · 7 citations
Computer Science · Engineering · #Complexity and Algorithms in Graphs #FOS: Computer and information sciences #FOS: Mathematics #Machine Learning (cs.LG) #Machine Learning (stat.ML) #Optimization and Control (math.OC) #Sparse and Compressive Sensing Techniques #Stochastic Gradient Optimization Techniques
paper · pdf · doi:10.48550/arxiv.2104.08708
openalex publication_date 2021/04/18 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
We provide a first-order oracle complexity lower bound for finding stationary points of min-max optimization problems where the objective function is smooth, nonconvex in the minimization variable, and strongly concave in the maximization variable. We establish a lower bound of Ω(√κε-2) for deterministic oracles, where ε defines the level of approximate stationarity and κ is the condition number. Our analysis shows that the upper bound achieved in (Lin et al., 2020b) is optimal in the ε and κ dependence up to logarithmic factors. For stochastic oracles, we provide a lower bound of Ω(√κε-2 + κ1/3ε-4). It suggests that there is a significant gap between the upper bound O(κ3 ε-4) in (Lin et al., 2020a) and our lower bound in the condition number dependence.