Why Does Deep and Cheap Learning Work So Well?

© 2017, Springer Science+Business Media, LLC. We show how the success of deep learning could depend not only on mathematics but also on physics: although well-known mathematical theorems guarantee that neural networks can approximate arbitrary functions well, the class of functions of practical inte...

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Main Authors: Lin, Henry W, Tegmark, Max, Rolnick, David
Format: Article
Language:English
Published: Springer Nature 2021
Online Access:https://hdl.handle.net/1721.1/135715
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author Lin, Henry W
Tegmark, Max
Rolnick, David
author_facet Lin, Henry W
Tegmark, Max
Rolnick, David
author_sort Lin, Henry W
collection MIT
description © 2017, Springer Science+Business Media, LLC. We show how the success of deep learning could depend not only on mathematics but also on physics: although well-known mathematical theorems guarantee that neural networks can approximate arbitrary functions well, the class of functions of practical interest can frequently be approximated through “cheap learning” with exponentially fewer parameters than generic ones. We explore how properties frequently encountered in physics such as symmetry, locality, compositionality, and polynomial log-probability translate into exceptionally simple neural networks. We further argue that when the statistical process generating the data is of a certain hierarchical form prevalent in physics and machine learning, a deep neural network can be more efficient than a shallow one. We formalize these claims using information theory and discuss the relation to the renormalization group. We prove various “no-flattening theorems” showing when efficient linear deep networks cannot be accurately approximated by shallow ones without efficiency loss; for example, we show that n variables cannot be multiplied using fewer than 2 n neurons in a single hidden layer.
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spelling mit-1721.1/1357152022-04-01T14:44:57Z Why Does Deep and Cheap Learning Work So Well? Lin, Henry W Tegmark, Max Rolnick, David © 2017, Springer Science+Business Media, LLC. We show how the success of deep learning could depend not only on mathematics but also on physics: although well-known mathematical theorems guarantee that neural networks can approximate arbitrary functions well, the class of functions of practical interest can frequently be approximated through “cheap learning” with exponentially fewer parameters than generic ones. We explore how properties frequently encountered in physics such as symmetry, locality, compositionality, and polynomial log-probability translate into exceptionally simple neural networks. We further argue that when the statistical process generating the data is of a certain hierarchical form prevalent in physics and machine learning, a deep neural network can be more efficient than a shallow one. We formalize these claims using information theory and discuss the relation to the renormalization group. We prove various “no-flattening theorems” showing when efficient linear deep networks cannot be accurately approximated by shallow ones without efficiency loss; for example, we show that n variables cannot be multiplied using fewer than 2 n neurons in a single hidden layer. 2021-10-27T20:28:58Z 2021-10-27T20:28:58Z 2017 2019-06-12T12:41:21Z Article http://purl.org/eprint/type/JournalArticle https://hdl.handle.net/1721.1/135715 en 10.1007/S10955-017-1836-5 Journal of Statistical Physics Creative Commons Attribution-Noncommercial-Share Alike http://creativecommons.org/licenses/by-nc-sa/4.0/ application/pdf Springer Nature arXiv
spellingShingle Lin, Henry W
Tegmark, Max
Rolnick, David
Why Does Deep and Cheap Learning Work So Well?
title Why Does Deep and Cheap Learning Work So Well?
title_full Why Does Deep and Cheap Learning Work So Well?
title_fullStr Why Does Deep and Cheap Learning Work So Well?
title_full_unstemmed Why Does Deep and Cheap Learning Work So Well?
title_short Why Does Deep and Cheap Learning Work So Well?
title_sort why does deep and cheap learning work so well
url https://hdl.handle.net/1721.1/135715
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