Whereas the achievable limits in terms of regret minimization in simple bandit models are now well known, it is often meaningful to consider slightly different goals and/or slightly different models.
In this talk, I first present recent contributions to a better understanding of the complexity of identifying the m-best arms. Generic notions of complexity are introduced and investigated for the two dominant frameworks considered in the literature: fixed-budget and fixed-confidence settings.
Then, I present optimal discovery with probabilistic expert advice, a problem arising from security analysis of power systems. While not involving a bandit model, I will show how some basic ideas of the bandit literature still lead to optimal solutions.