In this paper, we consider a finite-horizon model with the time-additive utility and the time varying discount rate. With the assumption of the concavity of absolute risk tolerance, the concavity of the consumption function has been proved. This result significantly broadens the conclusion of...

This article uses the <italic>Z</italic>-transform to develop a method for solving the linearised multidimensional discrete-time systems, which can be used to discuss the effects of policies on economy (including the welfare gains and initial effects on economy) raised by multi-sector...