  In the last decade, there have been significant advances in multi-agent
reinforcement learning (MARL) but there are still numerous challenges, such as
high sample complexity and slow convergence to stable policies, that need to be
overcome before wide-spread deployment is possible. However, many real-world
environments already, in practice, deploy sub-optimal or heuristic approaches
for generating policies. An interesting question that arises is how to best use
such approaches as advisors to help improve reinforcement learning in
multi-agent domains. In this paper, we provide a principled framework for
incorporating action recommendations from online sub-optimal advisors in
multi-agent settings. We describe the problem of ADvising Multiple Intelligent
Reinforcement Agents (ADMIRAL) in nonrestrictive general-sum stochastic game
environments and present two novel Q-learning based algorithms: ADMIRAL -
Decision Making (ADMIRAL-DM) and ADMIRAL - Advisor Evaluation (ADMIRAL-AE),
which allow us to improve learning by appropriately incorporating advice from
an advisor (ADMIRAL-DM), and evaluate the effectiveness of an advisor
(ADMIRAL-AE). We analyze the algorithms theoretically and provide fixed-point
guarantees regarding their learning in general-sum stochastic games.
Furthermore, extensive experiments illustrate that these algorithms: can be
used in a variety of environments, have performances that compare favourably to
other related baselines, can scale to large state-action spaces, and are robust
to poor advice from advisors.
