Procedure for Retracting Assumptions
Some node of the JTMS may represent contradictory situations which may arise during the activity of the PS.
Whenever a contradiction node is marked IN, the procedure for retracting assumptions is activated.
In JTMS the procedure is implemented through dependency-directed backtracking (DDB), aimed at identifying which currently believed assumption is responsible for the contradiction and at removing it, obtaining in such a way a relaxed set of nodes.