The nonlinear nature of plans

TLDR

Plans are typically viewed as linear sequences of actions executed one step at a time, yet they are not inherently constrained to linearity. This paper aims to introduce the procedural net, an information structure that represents a plan as a partial ordering of actions relative to time. The procedural net allows a problem‑solving system to postpone commitments to specific action orders, thereby enabling flexible planning. Using this representation, the system can directly and easily solve problems that would otherwise be very difficult.

Abstract

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 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 respec 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.