Equalizing Closeness Centralities via Edge Additions

Fuente: arXiv
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Main Authors: Crane, Alex, Friedler, Sorelle A., Patel, Mihir, Sullivan, Blair D.
Format: Preprint
Published: 2025
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author Crane, Alex
Friedler, Sorelle A.
Patel, Mihir
Sullivan, Blair D.
author_facet Crane, Alex
Friedler, Sorelle A.
Patel, Mihir
Sullivan, Blair D.
contents Graph modification problems with the goal of optimizing some measure of a given node's network position have a rich history in the algorithms literature. Less commonly explored are modification problems with the goal of equalizing positions, though this class of problems is well-motivated from the perspective of equalizing social capital, i.e., algorithmic fairness. In this work, we study how to add edges to make the closeness centralities of a given pair of nodes more equal. We formalize two versions of this problem: Closeness Ratio Improvement, which aims to maximize the ratio of closeness centralities between two specified nodes, and Closeness Gap Minimization, which aims to minimize the absolute difference of centralities. We show that both problems are $\textsf{NP}$-hard, and for Closeness Ratio Improvement we present a quasilinear-time $\frac{6}{11}$-approximation, complemented by a bicriteria inapproximability bound. In contrast, we show that Closeness Gap Minimization admits no multiplicative approximation unless $\textsf{P} = \textsf{NP}$. We conclude with a discussion of open directions for this style of problem, including several natural generalizations.
format Preprint
id arxiv_https___arxiv_org_abs_2505_06222
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Equalizing Closeness Centralities via Edge Additions
Crane, Alex
Friedler, Sorelle A.
Patel, Mihir
Sullivan, Blair D.
Data Structures and Algorithms
Social and Information Networks
Graph modification problems with the goal of optimizing some measure of a given node's network position have a rich history in the algorithms literature. Less commonly explored are modification problems with the goal of equalizing positions, though this class of problems is well-motivated from the perspective of equalizing social capital, i.e., algorithmic fairness. In this work, we study how to add edges to make the closeness centralities of a given pair of nodes more equal. We formalize two versions of this problem: Closeness Ratio Improvement, which aims to maximize the ratio of closeness centralities between two specified nodes, and Closeness Gap Minimization, which aims to minimize the absolute difference of centralities. We show that both problems are $\textsf{NP}$-hard, and for Closeness Ratio Improvement we present a quasilinear-time $\frac{6}{11}$-approximation, complemented by a bicriteria inapproximability bound. In contrast, we show that Closeness Gap Minimization admits no multiplicative approximation unless $\textsf{P} = \textsf{NP}$. We conclude with a discussion of open directions for this style of problem, including several natural generalizations.
title Equalizing Closeness Centralities via Edge Additions
topic Data Structures and Algorithms
Social and Information Networks
url https://arxiv.org/abs/2505.06222