David E. Smith and Mike Williamson
This paper describes: 1. A formal representation for such plans; it allows probabilistic, information-gathering actions, parallel execution, contingent execution, and loops. (Most existing plan representations could not express loops.) 2. An aggregation technique for evaluating such plans. This technique uses Markov modelling to recursively evaluate and simplify small fragments of the schematically represented plan. We are thus able to avoid constructing a Markov model for the entire plan.