ABSTRIPS (Planning In A Hierarchy of Abstraction Spaces) was considered the first program for plannings. In the program, the World as formulae set is represented by STRIPS. Each state of space set contains a World and a Goal set that is required to achieve. A stack with recursion is built to maintain Goals. The stacked top is matched with the current state, the goal is eliminated, and the stack is decremented. If a Goal consists of subGoals, then each plan is extracted from the top of the stack one after the other on successful matching with the stack’s top value. Read more

April, 1974