Critical Behavior in Physics and Probabilistic Formal Languages

We show that the mutual information between two symbols, as a function of the number of symbols between the two, decays exponentially in any probabilistic regular grammar, but can decay like a power law for a context-free grammar. This result about formal languages is closely related to a well-known...

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Main Authors: Lin, Henry, Tegmark, Max, Tegmark, Max Erik
Other Authors: Massachusetts Institute of Technology. Department of Physics
Format: Article
Published: MDPI AG 2018
Online Access:http://hdl.handle.net/1721.1/114221
https://orcid.org/0000-0001-7670-7190
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author Lin, Henry
Tegmark, Max
Tegmark, Max Erik
author2 Massachusetts Institute of Technology. Department of Physics
author_facet Massachusetts Institute of Technology. Department of Physics
Lin, Henry
Tegmark, Max
Tegmark, Max Erik
author_sort Lin, Henry
collection MIT
description We show that the mutual information between two symbols, as a function of the number of symbols between the two, decays exponentially in any probabilistic regular grammar, but can decay like a power law for a context-free grammar. This result about formal languages is closely related to a well-known result in classical statistical mechanics that there are no phase transitions in dimensions fewer than two. It is also related to the emergence of power law correlations in turbulence and cosmological inflation through recursive generative processes. We elucidate these physics connections and comment on potential applications of our results to machine learning tasks like training artificial recurrent neural networks. Along the way, we introduce a useful quantity, which we dub the rational mutual information, and discuss generalizations of our claims involving more complicated Bayesian networks. Keywords: formal languages; statistical mechanics; criticality
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spelling mit-1721.1/1142212022-09-27T18:49:37Z Critical Behavior in Physics and Probabilistic Formal Languages Lin, Henry Tegmark, Max Tegmark, Max Erik Massachusetts Institute of Technology. Department of Physics MIT Kavli Institute for Astrophysics and Space Research Tegmark, Max Erik We show that the mutual information between two symbols, as a function of the number of symbols between the two, decays exponentially in any probabilistic regular grammar, but can decay like a power law for a context-free grammar. This result about formal languages is closely related to a well-known result in classical statistical mechanics that there are no phase transitions in dimensions fewer than two. It is also related to the emergence of power law correlations in turbulence and cosmological inflation through recursive generative processes. We elucidate these physics connections and comment on potential applications of our results to machine learning tasks like training artificial recurrent neural networks. Along the way, we introduce a useful quantity, which we dub the rational mutual information, and discuss generalizations of our claims involving more complicated Bayesian networks. Keywords: formal languages; statistical mechanics; criticality 2018-03-19T18:54:50Z 2018-03-19T18:54:50Z 2017-06 2017-06 2018-02-16T19:12:38Z Article http://purl.org/eprint/type/JournalArticle 1099-4300 http://hdl.handle.net/1721.1/114221 Lin, Henry, and Max Tegmark. “Critical Behavior in Physics and Probabilistic Formal Languages.” Entropy 19, 12 (June 2017): 299 © 2017 The Author(s) https://orcid.org/0000-0001-7670-7190 http://dx.doi.org/10.3390/E19070299 Entropy Attribution 4.0 International (CC BY 4.0) https://creativecommons.org/licenses/by/4.0/ application/pdf MDPI AG MDPI
spellingShingle Lin, Henry
Tegmark, Max
Tegmark, Max Erik
Critical Behavior in Physics and Probabilistic Formal Languages
title Critical Behavior in Physics and Probabilistic Formal Languages
title_full Critical Behavior in Physics and Probabilistic Formal Languages
title_fullStr Critical Behavior in Physics and Probabilistic Formal Languages
title_full_unstemmed Critical Behavior in Physics and Probabilistic Formal Languages
title_short Critical Behavior in Physics and Probabilistic Formal Languages
title_sort critical behavior in physics and probabilistic formal languages
url http://hdl.handle.net/1721.1/114221
https://orcid.org/0000-0001-7670-7190
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