Topic summary
Policy function

Extracted from the Wikipedia article Bellman equation.
Analytical concepts in dynamic programming
The dynamic programming approach describes the optimal plan by finding a rule that tells what the controls should be, given any possible value of the state. For example, if consumption (c) depends only on wealth (W), we would seek a rule that gives consumption as a function of wealth. Such a rule, determining the controls as a function of the states, is called a policy function.