Fig 1. Our framework for task decomposition accounts for the computational cost of planning towards subgoals—task decompositions should jointly optimize task performance and the computational cost of search.

We formalize this in three nested layers of optimization: Action-Level Planning solves for a plan to accomplish a subgoal, which has a computational cost. Subgoal-Level Planning constructs subgoal sequences that maximize reward and minimize computational cost. Task Decomposition selects subgoals based on their value in Subgoal-Level Planning. This figure was adapted from a figure published in [12] (License: CC BY 4.0).