Coopetitive Index: a measure of cooperation and competition in coalition formation

Fuente: arXiv
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Main Authors: Aleandri, Michele, Dall'Aglio, Marco
Format: Preprint
Published: 2025
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author Aleandri, Michele
Dall'Aglio, Marco
author_facet Aleandri, Michele
Dall'Aglio, Marco
contents We extend the coopetition index introduced by Aleandri and Dall'Aglio (2025) for simple games to the broader class of monotone transferable utility (TU) games and to all non-empty coalitions, including singletons. The new formulation allows us to define an absolute coopetition index with a universal range in [-1,1], facilitating meaningful comparisons across coalitions. We study several notable instances of the index, including the Banzhaf, Uniform Shapley, and Shapley-Owen coopetition indices, and we derive explicit formulas that connect coopetition to classical semivalues. Finally, we provide axiomatic characterizations of the Uniform Shapley and Shaple--Owen versions, showing that each is uniquely determined by linearity, symmetry over pure bargaining games, external null player neutrality, and a contraction axiom reflecting its internal distribution. These results position the coopetition index as a versatile tool for quantifying the cooperative and competitive tendencies of coalitions in TU-games.
format Preprint
id arxiv_https___arxiv_org_abs_2511_15441
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Coopetitive Index: a measure of cooperation and competition in coalition formation
Aleandri, Michele
Dall'Aglio, Marco
Computer Science and Game Theory
We extend the coopetition index introduced by Aleandri and Dall'Aglio (2025) for simple games to the broader class of monotone transferable utility (TU) games and to all non-empty coalitions, including singletons. The new formulation allows us to define an absolute coopetition index with a universal range in [-1,1], facilitating meaningful comparisons across coalitions. We study several notable instances of the index, including the Banzhaf, Uniform Shapley, and Shapley-Owen coopetition indices, and we derive explicit formulas that connect coopetition to classical semivalues. Finally, we provide axiomatic characterizations of the Uniform Shapley and Shaple--Owen versions, showing that each is uniquely determined by linearity, symmetry over pure bargaining games, external null player neutrality, and a contraction axiom reflecting its internal distribution. These results position the coopetition index as a versatile tool for quantifying the cooperative and competitive tendencies of coalitions in TU-games.
title Coopetitive Index: a measure of cooperation and competition in coalition formation
topic Computer Science and Game Theory
url https://arxiv.org/abs/2511.15441