The nonlinear nature of plans
Earl D. Sacerdoti · Defense Technical Information Center (DTIC) · 1975
We usually think of plans as linear sequences of actions. This is because plans are usually executed one step at a time. But plans themselves are not constrained by physical limitations of linearity. This paper describes a new information structure, called the procedural net, that represents a plan as a partial ordering of actions with respect to time. By avoiding premature commitments to a particular order for achieving subgoals, a problem-solving system using this representation can deal easily and directly with problems that are otherwise very difficult to solve.