Introduction to PHATT planning approach

The problem in classical planning

Unfortunately, the problem of assigning each sequence to a strategy isn’t addressed by Ramírez and Geffner’s (2009) approach. To resolve this problem, Ramírez and Geffner (2010) proposed modifying their original approach using a probabilistic formulation of plan recognition that was still based on classical planning.

Usage of probabilities

With this approach, they tried to find the probability of a goal given some observations, formulated as $P (G|O)$, where $P$ is the probability, $G$ is the goal, and $O$ is a set of observations.