The connection between non-normality and trophic coherence in directed graphs

Trophic coherence and non-normality are both ways of describing the overall directionality of directed graphs or networks. Trophic coherence can be regarded as a measure of how neatly a graph can be divided into distinct layers, whereas non-normality is a measure of how unlike a matrix is with its t...

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Main Authors: Catherine Drysdale, Samuel Johnson
Format: Article
Language:English
Published: Frontiers Media S.A. 2025-01-01
Series:Frontiers in Applied Mathematics and Statistics
Subjects:
Online Access:https://www.frontiersin.org/articles/10.3389/fams.2024.1512865/full
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author Catherine Drysdale
Samuel Johnson
author_facet Catherine Drysdale
Samuel Johnson
author_sort Catherine Drysdale
collection DOAJ
description Trophic coherence and non-normality are both ways of describing the overall directionality of directed graphs or networks. Trophic coherence can be regarded as a measure of how neatly a graph can be divided into distinct layers, whereas non-normality is a measure of how unlike a matrix is with its transpose. We explore the relationship between trophic coherence and non-normality by first considering the connections that exist in literature and calculating the trophic coherence and non-normality for some toy networks. We then explore how persistence of an epidemic in an SIS model depends on coherence and how this relates to the non-normality. A similar effect on dynamics governed by a linear operator suggests that it may be useful to extend the concept of trophic coherence to matrices, which do not necessarily represent graphs.
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spelling doaj-art-ad7786d554d54f49949dc794a29dfa9f2025-01-07T06:50:05ZengFrontiers Media S.A.Frontiers in Applied Mathematics and Statistics2297-46872025-01-011010.3389/fams.2024.15128651512865The connection between non-normality and trophic coherence in directed graphsCatherine Drysdale0Samuel Johnson1Centre for Systems Modelling and Quantitative Biomedicine, University of Birmingham, Edgbaston, United KingdomSchool of Mathematics, University of Birmingham, Edgbaston, United KingdomTrophic coherence and non-normality are both ways of describing the overall directionality of directed graphs or networks. Trophic coherence can be regarded as a measure of how neatly a graph can be divided into distinct layers, whereas non-normality is a measure of how unlike a matrix is with its transpose. We explore the relationship between trophic coherence and non-normality by first considering the connections that exist in literature and calculating the trophic coherence and non-normality for some toy networks. We then explore how persistence of an epidemic in an SIS model depends on coherence and how this relates to the non-normality. A similar effect on dynamics governed by a linear operator suggests that it may be useful to extend the concept of trophic coherence to matrices, which do not necessarily represent graphs.https://www.frontiersin.org/articles/10.3389/fams.2024.1512865/fulldirected graphstrophic coherencenon-normalitypseudospectratrophic levelsepidemic modeling
spellingShingle Catherine Drysdale
Samuel Johnson
The connection between non-normality and trophic coherence in directed graphs
Frontiers in Applied Mathematics and Statistics
directed graphs
trophic coherence
non-normality
pseudospectra
trophic levels
epidemic modeling
title The connection between non-normality and trophic coherence in directed graphs
title_full The connection between non-normality and trophic coherence in directed graphs
title_fullStr The connection between non-normality and trophic coherence in directed graphs
title_full_unstemmed The connection between non-normality and trophic coherence in directed graphs
title_short The connection between non-normality and trophic coherence in directed graphs
title_sort connection between non normality and trophic coherence in directed graphs
topic directed graphs
trophic coherence
non-normality
pseudospectra
trophic levels
epidemic modeling
url https://www.frontiersin.org/articles/10.3389/fams.2024.1512865/full
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