 The quadruple \(\mathcal{F} = (T,\prec,\mathcal{U},D)\) is called the augmented temporal frame of the model \(\mathcal{M}\). Since the model is supposed to represent the temporal evolution of the world, the local domains at the different time instants in the underlying augmented temporal frame must be suitably connected. There are four natural cases to distinguish for an augmented temporal frame, respectively for any first-order temporal model based on it: