optimization

Mode connectivity

The old picture of the loss surface as many isolated basins, one per initialization, has not held up. Freeman and Bruna [6] suggested early on that low-loss level sets stay connected. Garipov et al. [1]…

The neural tangent kernel

The neural tangent kernel was one of the few deep-learning theory ideas that were useful before they became a concept. It doesn't solve generalization, but it makes a very stubborn object analyzable.…

The implicit-bias program

Why does training a model without an explicit regularizer, with the loss driven nearly to zero, still produce a solution that generalizes? The classical answer is that the objective has to carry the…

The edge of stability

Cohen et al. [1] observed that gradient descent on neural networks spends most of training in a regime where the top Hessian eigenvalue…

Lottery ticket hypothesis

The lottery-ticket hypothesis of Frankle and Carbin [1] proposes that a randomly initialized dense network already contains a much sparser subnetwork (the "winning ticket") which, trained in isolation…

On flat minima

Whether flat minima generalize better than sharp ones has been an open question for about seven years. The debate seems to close every year and reopen a year later. Most readers entering the field…

Four explanations for Grokking

The network has generalized but long after it has already fit the data. The paper is Grokking: Generalization Beyond Overfitting on Small Algorithmic Datasets by Power et al. [1]. I came across it maybe a…