Constant Inapproximability for PPA

Fuente: arXiv
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Main Authors: Deligkas, Argyrios, Fearnley, John, Hollender, Alexandros, Melissourgos, Themistoklis
Format: Preprint
Published: 2022
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author Deligkas, Argyrios
Fearnley, John
Hollender, Alexandros
Melissourgos, Themistoklis
author_facet Deligkas, Argyrios
Fearnley, John
Hollender, Alexandros
Melissourgos, Themistoklis
contents In the $\varepsilon$-Consensus-Halving problem, we are given $n$ probability measures $v_1, \dots, v_n$ on the interval $R = [0,1]$, and the goal is to partition $R$ into two parts $R^+$ and $R^-$ using at most $n$ cuts, so that $|v_i(R^+) - v_i(R^-)| \leq \varepsilon$ for all $i$. This fundamental fair division problem was the first natural problem shown to be complete for the class PPA, and all subsequent PPA-completeness results for other natural problems have been obtained by reducing from it. We show that $\varepsilon$-Consensus-Halving is PPA-complete even when the parameter $\varepsilon$ is a constant. In fact, we prove that this holds for any constant $\varepsilon < 1/5$. As a result, we obtain constant inapproximability results for all known natural PPA-complete problems, including Necklace-Splitting, the Discrete-Ham-Sandwich problem, two variants of the pizza sharing problem, and for finding fair independent sets in cycles and paths.
format Preprint
id arxiv_https___arxiv_org_abs_2201_10011
institution arXiv
publishDate 2022
record_format arxiv
spellingShingle Constant Inapproximability for PPA
Deligkas, Argyrios
Fearnley, John
Hollender, Alexandros
Melissourgos, Themistoklis
Computational Complexity
Computer Science and Game Theory
In the $\varepsilon$-Consensus-Halving problem, we are given $n$ probability measures $v_1, \dots, v_n$ on the interval $R = [0,1]$, and the goal is to partition $R$ into two parts $R^+$ and $R^-$ using at most $n$ cuts, so that $|v_i(R^+) - v_i(R^-)| \leq \varepsilon$ for all $i$. This fundamental fair division problem was the first natural problem shown to be complete for the class PPA, and all subsequent PPA-completeness results for other natural problems have been obtained by reducing from it. We show that $\varepsilon$-Consensus-Halving is PPA-complete even when the parameter $\varepsilon$ is a constant. In fact, we prove that this holds for any constant $\varepsilon < 1/5$. As a result, we obtain constant inapproximability results for all known natural PPA-complete problems, including Necklace-Splitting, the Discrete-Ham-Sandwich problem, two variants of the pizza sharing problem, and for finding fair independent sets in cycles and paths.
title Constant Inapproximability for PPA
topic Computational Complexity
Computer Science and Game Theory
url https://arxiv.org/abs/2201.10011