Search for a moving target in a competitive environment

TL;DR

This paper analyzes a dynamic search game where multiple players compete to find a moving, invisible object, showing that equilibrium strategies are always greedy, maximizing immediate detection probability.

Contribution

It characterizes the subgame perfect equilibria of the search game as greedy strategies, providing a complete description of optimal play in this competitive setting.

Findings

Equilibria are exactly the set of greedy strategies.

Players always choose actions maximizing immediate detection probability.

The model extends to various game variations.

Abstract

We consider a discrete-time dynamic search game in which a number of players compete to find an invisible object that is moving according to a time-varying Markov chain. We examine the subgame perfect equilibria of these games. The main result of the paper is that the set of subgame perfect equilibria is exactly the set of greedy strategy profiles, i.e. those strategy profiles in which the players always choose an action that maximizes their probability of immediately finding the object. We discuss various variations and extensions of the model.