When Are Bias-Free ReLU Networks Like Linear Networks?
- URL: http://arxiv.org/abs/2406.12615v1
- Date: Tue, 18 Jun 2024 13:43:58 GMT
- Title: When Are Bias-Free ReLU Networks Like Linear Networks?
- Abstract summary: We show that bias-free ReLU networks have the same learning dynamics as linear networks.
While bias-free ReLU networks are more expressive than their two-layer counterparts, they still share a number of similarities with deep linear networks.
- Score: 7.197469507060226
- License: http://creativecommons.org/licenses/by-nc-nd/4.0/
- Abstract: We investigate the expressivity and learning dynamics of bias-free ReLU networks. We firstly show that two-layer bias-free ReLU networks have limited expressivity: the only odd function two-layer bias-free ReLU networks can express is a linear one. We then show that, under symmetry conditions on the data, these networks have the same learning dynamics as linear networks. This allows us to give closed-form time-course solutions to certain two-layer bias-free ReLU networks, which has not been done for nonlinear networks outside the lazy learning regime. While deep bias-free ReLU networks are more expressive than their two-layer counterparts, they still share a number of similarities with deep linear networks. These similarities enable us to leverage insights from linear networks, leading to a novel understanding of bias-free ReLU networks. Overall, our results show that some properties established for bias-free ReLU networks arise due to equivalence to linear networks, and suggest that including bias or considering asymmetric data are avenues to engage with nonlinear behaviors.
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