Problem Description Language

A Problem Description Language is a logical language for the components of a Search Problem. So basically a level higher than the previous logics Propositional Logic and First-Order Predicate Logic.

In particular it describes:

• possible states (predicates)
• initial state $I$
• goal test $G$
• set $A$ of actions in terms of
  • Precondition
  • Effect (replaces Frame Axioms in Frame Problem)
  • (compare with Transition Model)

A logicial description of all of these parts is called a Planning Task. And a solution to this is called Plan which we try to find via planning.