  This paper presents a multiplayer Homicidal Chauffeur reach-avoid
differential game, which involves Dubins-car pursuers and simple-motion
evaders. The goal of the pursuers is to cooperatively protect a planar convex
region from the evaders, who strive to reach the region. We propose a
cooperative strategy for the pursuers based on subgames for multiple pursuers
against one evader and optimal task allocation. We introduce pursuit enclosure
functions (PEFs) and propose a new enclosure region pursuit (ERP) winning
approach that supports forward analysis for the strategy synthesis in the
subgames. We show that if a pursuit coalition is able to defend the region
against an evader under the ERP winning, then no more than two pursuers in the
coalition are necessarily needed. We also propose a steer-to-ERP approach to
certify the ERP winning and synthesize the ERP winning strategy. To implement
the strategy, we introduce a positional PEF and provide the necessary
parameters, states, and strategies that ensure the ERP winning for both one
pursuer and two pursuers against one evader. Additionally, we formulate a
binary integer program using the subgame outcomes to maximize the captured
evaders in the ERP winning for the pursuit task allocation. Finally, we propose
a multiplayer receding-horizon strategy where the ERP winnings are checked in
each horizon, the task is allocated, and the strategies of the pursuers are
determined. Numerical examples are provided to illustrate the results.
