CAD.3:2 - Problem

The layers can make mutually inconsistent promises. The tracker guarantees a small error only for modest commands, while the planner assumes that error before restricting its commands. Tightening an upper constraint by an arbitrary tolerance conceals that circular dependence. A feasible first command can also lead to a state from which no later command is feasible.

The construction must close both the simultaneous compatibility question and the continuation question.