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arXiv · 2202.00856

The Role of Linear Layers in Nonlinear Interpolating Networks

Greg Ongie·Rebecca Willett
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Abstract

This paper explores the implicit bias of overparameterized neural networks of depth greater than two layers. Our framework considers a family of networks of varying depth that all have the same capacity but different implicitly defined representation costs. The representation cost of a function induced by a neural network architecture is the minimum sum of squared weights needed for the network to represent the function; it reflects the function space bias associated with the architecture. Our results show that adding linear layers to a ReLU network yields a representation cost that reflects a complex interplay between the alignment and sparsity of ReLU units. Specifically, using a neural network to fit training data with minimum representation cost yields an interpolating function that is constant in directions perpendicular to a low-dimensional subspace on which a parsimonious interpolant exists.

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Greg Ongie, Rebecca Willett. 2022-02-02. The Role of Linear Layers in Nonlinear Interpolating Networks. https://arxiv.org/abs/2202.00856

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