Data Symmetries and Learning in Fully Connected Neural Networks

Symmetries in the data and how they constrain the learned weights of modern deep networks is still an open problem. In this work we study the simple case of fully connected shallow non-linear neural networks and consider two types of symmetries: full dataset symmetries where the dataset <inline-f...

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Main Authors: Fabio Anselmi, Luca Manzoni, Alberto D'onofrio, Alex Rodriguez, Giulio Caravagna, Luca Bortolussi, Francesca Cairoli
Format: Article
Language:English
Published: IEEE 2023-01-01
Series:IEEE Access
Subjects:
Online Access:https://ieeexplore.ieee.org/document/10122571/
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author Fabio Anselmi
Luca Manzoni
Alberto D'onofrio
Alex Rodriguez
Giulio Caravagna
Luca Bortolussi
Francesca Cairoli
author_facet Fabio Anselmi
Luca Manzoni
Alberto D'onofrio
Alex Rodriguez
Giulio Caravagna
Luca Bortolussi
Francesca Cairoli
author_sort Fabio Anselmi
collection DOAJ
description Symmetries in the data and how they constrain the learned weights of modern deep networks is still an open problem. In this work we study the simple case of fully connected shallow non-linear neural networks and consider two types of symmetries: full dataset symmetries where the dataset <inline-formula> <tex-math notation="LaTeX">$X$ </tex-math></inline-formula> is mapped into itself by any transformation <inline-formula> <tex-math notation="LaTeX">$g$ </tex-math></inline-formula>, i.e. <inline-formula> <tex-math notation="LaTeX">$gX=X$ </tex-math></inline-formula> or single data point symmetries where <inline-formula> <tex-math notation="LaTeX">$gx=x$ </tex-math></inline-formula>, <inline-formula> <tex-math notation="LaTeX">$x\in X$ </tex-math></inline-formula>. We prove and experimentally confirm that symmetries in the data are directly inherited at the level of the network&#x2019;s learned weights and relate these findings with the common practice of data augmentation in modern machine learning. Finally, we show how symmetry constraints have a profound impact on the spectrum of the learned weights, an aspect of the so-called network implicit bias.
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spelling doaj.art-6ef8851554c34f7c87ec8206b6585ca62023-05-19T23:01:11ZengIEEEIEEE Access2169-35362023-01-0111472824729010.1109/ACCESS.2023.327493810122571Data Symmetries and Learning in Fully Connected Neural NetworksFabio Anselmi0https://orcid.org/0000-0002-0264-4761Luca Manzoni1https://orcid.org/0000-0001-6312-7728Alberto D'onofrio2Alex Rodriguez3Giulio Caravagna4https://orcid.org/0000-0003-4240-3265Luca Bortolussi5https://orcid.org/0000-0001-8874-4001Francesca Cairoli6Department of Mathematics and Geosciences, University of Trieste, Trieste, ItalyDepartment of Mathematics and Geosciences, University of Trieste, Trieste, ItalyDepartment of Mathematics and Geosciences, University of Trieste, Trieste, ItalyDepartment of Mathematics and Geosciences, University of Trieste, Trieste, ItalyDepartment of Mathematics and Geosciences, University of Trieste, Trieste, ItalyDepartment of Mathematics and Geosciences, University of Trieste, Trieste, ItalyDepartment of Mathematics and Geosciences, University of Trieste, Trieste, ItalySymmetries in the data and how they constrain the learned weights of modern deep networks is still an open problem. In this work we study the simple case of fully connected shallow non-linear neural networks and consider two types of symmetries: full dataset symmetries where the dataset <inline-formula> <tex-math notation="LaTeX">$X$ </tex-math></inline-formula> is mapped into itself by any transformation <inline-formula> <tex-math notation="LaTeX">$g$ </tex-math></inline-formula>, i.e. <inline-formula> <tex-math notation="LaTeX">$gX=X$ </tex-math></inline-formula> or single data point symmetries where <inline-formula> <tex-math notation="LaTeX">$gx=x$ </tex-math></inline-formula>, <inline-formula> <tex-math notation="LaTeX">$x\in X$ </tex-math></inline-formula>. We prove and experimentally confirm that symmetries in the data are directly inherited at the level of the network&#x2019;s learned weights and relate these findings with the common practice of data augmentation in modern machine learning. Finally, we show how symmetry constraints have a profound impact on the spectrum of the learned weights, an aspect of the so-called network implicit bias.https://ieeexplore.ieee.org/document/10122571/Artificial neural networkssymmetry invarianceequivariance
spellingShingle Fabio Anselmi
Luca Manzoni
Alberto D'onofrio
Alex Rodriguez
Giulio Caravagna
Luca Bortolussi
Francesca Cairoli
Data Symmetries and Learning in Fully Connected Neural Networks
IEEE Access
Artificial neural networks
symmetry invariance
equivariance
title Data Symmetries and Learning in Fully Connected Neural Networks
title_full Data Symmetries and Learning in Fully Connected Neural Networks
title_fullStr Data Symmetries and Learning in Fully Connected Neural Networks
title_full_unstemmed Data Symmetries and Learning in Fully Connected Neural Networks
title_short Data Symmetries and Learning in Fully Connected Neural Networks
title_sort data symmetries and learning in fully connected neural networks
topic Artificial neural networks
symmetry invariance
equivariance
url https://ieeexplore.ieee.org/document/10122571/
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