A multi-agent system is composed of multiple autonomous entities, with distributed information, computational ability, and possibly divergent interests. Multi-agent systems may be cooperative, such as sensor networks and mobile robots in a warehouse, or competitive, such as in electronic commerce, or in settings of resource or task allocation. Some systems are somewhere in between, for example Wikipedia and StackOverflow. The agents in a multi-agent system may be both artificial and human (and often humans are present at least on the edges of these systems.)