Momentary equilibria are defined as points that satisfy agents' optimality conditions and market clearing at any date. However, some dynamic sequences commencing from such points may not be considered valid equilibria because they asymptotically violate some economic restriction of the model....

Approaching demographic shifts are raising concerns about fiscal sustainability in most OECD countries. A widespread view based on the tax-smoothing idea is that a prior consolidation of public finances is required to cope with the predicted trend deterioration in the primary budget balance....