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Main Authors: Zhang, Edith, Scott, James, Du, Qiang, Porter, Mason A.
Format: Preprint
Published: 2024
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Online Access:https://arxiv.org/abs/2408.00422
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author Zhang, Edith
Scott, James
Du, Qiang
Porter, Mason A.
author_facet Zhang, Edith
Scott, James
Du, Qiang
Porter, Mason A.
contents Ginzburg--Landau (GL) functionals on graphs, which are relaxations of graph-cut functionals on graphs, have yielded a variety of insights in image segmentation and graph clustering. In this paper, we study large-graph limits of GL functionals by taking a functional-analytic view of graphs as nonlocal kernels. For a graph $W_n$ with $n$ nodes, the corresponding graph GL functional $\GL^{W_n}_\ep$ is an energy for functions on $W_n$. We minimize GL functionals on sequences of growing graphs that converge to functions called graphons. For such sequences of graphs, we show that the graph GL functional $Γ$-converges to a continuous and nonlocal functional that we call the \emph{graphon GL functional}. We also investigate the sharp-interface limits of the graph GL and graphon GL functionals, and we relate these limits to a nonlocal total-variation (TV) functional. We express the limiting GL functional in terms of Young measures and thereby obtain a probabilistic interpretation of the variational problem in the large-graph limit. Finally, to develop intuition about the graphon GL functional, we determine the GL minimizer for several example families of graphons.
format Preprint
id arxiv_https___arxiv_org_abs_2408_00422
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Ginzburg--Landau Functionals in the Large-Graph Limit
Zhang, Edith
Scott, James
Du, Qiang
Porter, Mason A.
Functional Analysis
Social and Information Networks
Combinatorics
Probability
Ginzburg--Landau (GL) functionals on graphs, which are relaxations of graph-cut functionals on graphs, have yielded a variety of insights in image segmentation and graph clustering. In this paper, we study large-graph limits of GL functionals by taking a functional-analytic view of graphs as nonlocal kernels. For a graph $W_n$ with $n$ nodes, the corresponding graph GL functional $\GL^{W_n}_\ep$ is an energy for functions on $W_n$. We minimize GL functionals on sequences of growing graphs that converge to functions called graphons. For such sequences of graphs, we show that the graph GL functional $Γ$-converges to a continuous and nonlocal functional that we call the \emph{graphon GL functional}. We also investigate the sharp-interface limits of the graph GL and graphon GL functionals, and we relate these limits to a nonlocal total-variation (TV) functional. We express the limiting GL functional in terms of Young measures and thereby obtain a probabilistic interpretation of the variational problem in the large-graph limit. Finally, to develop intuition about the graphon GL functional, we determine the GL minimizer for several example families of graphons.
title Ginzburg--Landau Functionals in the Large-Graph Limit
topic Functional Analysis
Social and Information Networks
Combinatorics
Probability
url https://arxiv.org/abs/2408.00422