11.2 STN Planning 231
This chapter describes ways to represent HTN planning problems and algorithms
for solving the problems. The presentation draws loosely from ideas developed by
Sacerdoti [460], Tate [503], Wilkins [549], Erol et al. [174], and Nau et al. [413, 414].
Sections 11.2 through 11.4 discuss a simplified version of HTN planning that we
will call Simple Task Network (STN) planning. Section 11.2 describes the repre-
sentation scheme, Section 11.3 discusses a planning procedure for a case in which
the tasks are totally ordered, and Section 11.4 describes a planning procedure for a
more general case in which the tasks may be partially ordered (e.g., to specify that
we don’t care about the order in which the stacks are moved). Section 11.5