  Model checking of strategic abilities is a notoriously hard problem, even
more so in the realistic case of agents with imperfect information.
Assume-guarantee reasoning can be of great help here, providing a way to
decompose the complex problem into a small set of exponentially easier
subproblems. In this paper, we propose two schemes for assume-guarantee
verification of alternating-time temporal logic with imperfect information. We
prove the soundness of both schemes, and discuss their completeness. We
illustrate the method by examples based on known benchmarks, and show
experimental results that demonstrate the practical benefits of the approach.
