Title: Are Saddles Good Enough for Deep Learning?,
Abstract: Recent years have seen a growing interest in understanding deep neural
networks from an optimization perspective. It is understood now that converging
to low-cost local minima is sufficient for such models to become effective in
practice. However, in this work, we propose a new hypothesis based on recent
theoretical findings and empirical studies that deep neural network models
actually converge to saddle points with high degeneracy. Our findings from this
work are new, and can have a significant impact on the development of gradient
descent based methods for training deep networks. We validated our hypotheses
using an extensive experimental evaluation on standard datasets such as MNIST
and CIFAR-10, and also showed that recent efforts that attempt to escape
saddles finally converge to saddles with high degeneracy, which we define as
`good saddles'. We also verified the famous Wigner's Semicircle Law in our
experimental results.