GPT-5.6 Assists in Proving Lower Bound for Gradient Descent Acceleration

prof_grimmer · x · 2026-08-12

A new paper by Jianhao Ma and Yuxin Chen establishes a lower bound of $\Omega(T^{-1.9319})$ for the last-iterate convergence rate of gradient descent (GD) with predetermined stepsize schedules.

This rigorously proves that stepsize schedules alone cannot accelerate plain GD to the optimal $O(T^{-2})$ rate of general first-order methods. Notably, the paper states the proof was developed under the authors' guidance by GPT-5.6 Sol Pro.

Related event: GPT-Assisted Proof Reveals Theoretical Limits of Gradient Descent(4 posts)→

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