期刊名称:International Journal of Mathematics and Mathematical Sciences
印刷版ISSN:0161-1712
电子版ISSN:1687-0425
出版年度:2005
卷号:2005
DOI:10.1155/IJMMS.2005.57
出版社:Hindawi Publishing Corporation
摘要:We consider the problem of selecting an optimality criterion, when
total costs diverge, in deterministic infinite horizon
optimization over discrete time. Our formulation allows for both
discrete and continuous state and action spaces, as well as
time-varying, that is, nonstationary, data. The task is to choose
a criterion that is neither too overselective, so that no
policy is optimal, nor too underselective, so that most
policies are optimal. We contrast and compare the following
optimality criteria: strong, overtaking, weakly overtaking,
efficient, and average. However, our focus is on the optimality
criterion of efficiency. (A solution is efficient if it
is optimal to each of the states through which it passes.) Under
mild regularity conditions, we show that efficient solutions
always exist and thus are not overselective. As to
underselectivity, we provide weak state reachability conditions
which assure that every efficient solution is also average
optimal, thus providing a sufficient condition for average optima
to exist. Our main result concerns the case where the discounted
per-period costs converge to zero, while the discounted total
costs diverge to infinity. Under the assumption that we can reach
from any feasible state any feasible sequence of states in
bounded time, we show that every efficient solution is also
overtaking, thus providing a sufficient condition for overtaking
optima to exist.