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Main Authors: Yaish, Aviv, Chemaya, Nir, Malkhi, Dahlia, Cong, Lin William
Format: Preprint
Published: 2025
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Online Access:https://arxiv.org/abs/2508.04668
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author Yaish, Aviv
Chemaya, Nir
Malkhi, Dahlia
Cong, Lin William
author_facet Yaish, Aviv
Chemaya, Nir
Malkhi, Dahlia
Cong, Lin William
contents Inequality measures such as the Gini coefficient are used to inform and motivate policymaking, and are increasingly applied to digital platforms. We analyze how measures fare in pseudonymous settings that are common in the digital age. One key challenge of such environments is the ability of actors to create fake identities under fictitious false names, also known as ``Sybils.'' While some actors may do so to preserve their privacy, we show that this can hamper inequality measurements: it is impossible for measures satisfying the literature's canonical set of desired properties to assess the inequality of an economy that may harbor Sybils. We characterize the class of all Sybil-proof measures, and prove that they must satisfy relaxed version of the aforementioned properties. Furthermore, we show that the structure imposed restricts the ability to assess inequality at a fine-grained level. We then apply our results to prove that popular measures are not Sybil-proof, with the famous Gini coefficient being but one example out of many. Finally, we examine dynamics leading to the creation of Sybils in digital and traditional settings.
format Preprint
id arxiv_https___arxiv_org_abs_2508_04668
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Inequality in the Age of Pseudonymity
Yaish, Aviv
Chemaya, Nir
Malkhi, Dahlia
Cong, Lin William
Computer Science and Game Theory
Computers and Society
Theoretical Economics
Inequality measures such as the Gini coefficient are used to inform and motivate policymaking, and are increasingly applied to digital platforms. We analyze how measures fare in pseudonymous settings that are common in the digital age. One key challenge of such environments is the ability of actors to create fake identities under fictitious false names, also known as ``Sybils.'' While some actors may do so to preserve their privacy, we show that this can hamper inequality measurements: it is impossible for measures satisfying the literature's canonical set of desired properties to assess the inequality of an economy that may harbor Sybils. We characterize the class of all Sybil-proof measures, and prove that they must satisfy relaxed version of the aforementioned properties. Furthermore, we show that the structure imposed restricts the ability to assess inequality at a fine-grained level. We then apply our results to prove that popular measures are not Sybil-proof, with the famous Gini coefficient being but one example out of many. Finally, we examine dynamics leading to the creation of Sybils in digital and traditional settings.
title Inequality in the Age of Pseudonymity
topic Computer Science and Game Theory
Computers and Society
Theoretical Economics
url https://arxiv.org/abs/2508.04668