# Attacking Power Indices by Manipulating Player Reliability

## TL;DR

This paper explores how manipulating player participation probabilities can influence power indices in cooperative games, providing algorithms for certain game types and highlighting intractability in others.

## Contribution

It introduces algorithms for manipulating power indices in specific classes of cooperative games and demonstrates the computational complexity of the problem.

## Key findings

- Algorithms are effective for network centrality and influence attribution games.
- Manipulation problems are tractable in some cases but intractable in others.
- Computing power indices remains feasible even when manipulation is hard.

## Abstract

We investigate the manipulation of power indices in TU-cooperative games by stimulating (subject to a budget constraint) changes in the propensity of other players to participate to the game. We display several algorithms that show that the problem is often tractable for so-called network centrality games and influence attribution games, as well as an example when optimal manipulation is intractable, even though computing power indices is feasible.