SAT encodings of HTN planning
Abstract actions can be seen as disjunctive constraints
- K-step encoding has each of the steps mapped to a disjunction of the non-primitive tasks
- If a step s is mapped to a task N, then one of the reductions of N must hold (**The heart of encoding setup**)
- + The normal constraints of primitive action-based encoding
- Causal encodings seem to be a natural fit (given the causal dependencies encoded in reduction schemas)
[Mali & Kambampati, AIPS-98]