Abstract
We extend hierarchical task network planning with
task insertion (TIHTN) by introducing state constraints, called TIHTNS. We show that just as for
TIHTN planning, all solutions of the TIHTNS planning problem can be obtained by acyclic decomposition and task insertion, entailing that its planexistence problem is decidable without any restriction on decomposition methods. We also prove
that the extension by state constraints does not increase the complexity of the plan-existence problem, which stays 2-NEXPTIME-complete, based
on an acyclic progression operator. In addition,
we show that TIHTNS planning covers not only
the original TIHTN planning but also hierarchyrelaxed hierarchical goal network planning