arXiv Machine Learning

On the stability of learning

The paper investigates how learning algorithms behave when gradient signals are noisy, sparse, and intermittently available, as often occurs in biological neural networks. It demonstrates that even if the average learning dynamics converge to the correct optimum, the variance of learning can become asymptotically infinite, leading to instability. The authors analyze several analytically tractable settings—including single-layer and multi-layer linear networks—to derive explicit conditions under which learning remains stable, highlighting that unbiased credit assignment alone is insufficient without sufficiently frequent and informative feedback.

arXiv AI
Oct 12

On the Rate of Convergence of GD in Non-linear Neural Networks: An Adversarial Robustness Perspective

The paper analyzes Gradient Descent (GD) on a minimal binary classification problem with a two‑neuron ReLU network trained on two instances. It proves that GD converges to an optimal robustness margin—maximizing the distance between the decision boundary and training points—but does so at a very slow rate, specifically θ(1/ln(t)). Empirical simulations confirm this slow convergence across various initializations, and the authors provide a rigorous analysis of GD trajectories across different activation patterns to establish the first explicit lower bound on robustness convergence in a non‑linear model.

By Guy Smorodinsky, Sveta Gimpleson, Itay Safran
arXiv AI
Jun 29

Derivation of effective gradient flow equations and dynamical truncation of training data in Deep Learning

arXiv:2501. 07400v2 Announce Type: replace-cross Abstract: We derive explicit equations governing the cumulative biases and weights in Deep Learning with ReLU activation function, based on gradient descent for the Euclidean loss in the input layer, and under the assumption that the weights are, in a precise sense, adapted to the coordinate system distinguished by the activations.

By Thomas Chen
arXiv Statistics ML
Oct 26

Convergence of Large-Stepsize SGD for the Cross-entropy Loss via Stochastic Lyapunov Stability

The paper presents convergence guarantees for Stochastic Gradient Descent (SGD) applied to the multiclass cross-entropy loss in both linear classifiers and two-layer neural networks. It shows that SGD dynamics can oscillate between an edge-of-stability regime dominated by curvature-driven oscillations and a stable regime where the expected loss decreases at a controlled rate. Despite these oscillations, the authors prove that SGD stabilizes the dynamics, ensuring that iterates return to stability within a fixed number of iterations and enabling convergence in the best-iterate sense even with large learning rates.

By Konstantinos Emmanouilidis, Lachlan MacDonald, Salma Tarmoun, Rene Vidal