Temporal Constraints on Trajectories in Qualitative

State space equations that constrain the values of related variables within individual states are often used in models of continuous dynamical systems such as ordinary differential equations . These models do not allow the representation of non-local information constraining the behavior of the system across time except through the application of continuity . Qualitative simulation (Kuipers, 1994 ; Forbus, 1984) uses an abstraction of ordinary differential equations to specify structural equations based on a state space description . The discretization of trajectories into abstract qualitative states, however, makes the representation