Beyond Exact Fairness: Envy-Free Incomplete Connected Fair Division

Fuente: arXiv
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Main Authors: S, Ajaykrishnan E, Lokshtanov, Daniel
Format: Preprint
Published: 2025
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author S, Ajaykrishnan E
Lokshtanov, Daniel
author_facet S, Ajaykrishnan E
Lokshtanov, Daniel
contents We study the problem of Envy-Free Incomplete Connected Fair Division, where exactly p vertices of an undirected graph must be allocated to agents such that each agent receives a connected share and does not envy another agent's share. Focusing on agents with additive valuations, we show that the problem remains computationally hard when parameterized by p and the number of agents. This result holds even for star graphs and with the input numbers given in unary representation, thereby resolving an open problem posed by Gahlawat and Zehavi (FSTTCS 2023). In stark contrast, we show that if one is willing to tolerate even the slightest amount of envy, then the problem becomes efficient with respect to the natural parameters. Specifically, we design an Efficient Parameterized Approximation Scheme parameterized by p and the number of agent types. Our algorithm works on general graphs and remains efficient even when the input numbers are provided in binary representation.
format Preprint
id arxiv_https___arxiv_org_abs_2512_22475
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Beyond Exact Fairness: Envy-Free Incomplete Connected Fair Division
S, Ajaykrishnan E
Lokshtanov, Daniel
Data Structures and Algorithms
Computer Science and Game Theory
We study the problem of Envy-Free Incomplete Connected Fair Division, where exactly p vertices of an undirected graph must be allocated to agents such that each agent receives a connected share and does not envy another agent's share. Focusing on agents with additive valuations, we show that the problem remains computationally hard when parameterized by p and the number of agents. This result holds even for star graphs and with the input numbers given in unary representation, thereby resolving an open problem posed by Gahlawat and Zehavi (FSTTCS 2023). In stark contrast, we show that if one is willing to tolerate even the slightest amount of envy, then the problem becomes efficient with respect to the natural parameters. Specifically, we design an Efficient Parameterized Approximation Scheme parameterized by p and the number of agent types. Our algorithm works on general graphs and remains efficient even when the input numbers are provided in binary representation.
title Beyond Exact Fairness: Envy-Free Incomplete Connected Fair Division
topic Data Structures and Algorithms
Computer Science and Game Theory
url https://arxiv.org/abs/2512.22475