This section is provided mainly to help to explain similar concepts that are coming in later sections. The presentation is limited to discrete spaces, which are much simpler to formulate and understand. Following this, an extension to configuration spaces and other continuous state spaces can be made. The discussion here is also relevant background for the feedback planning concepts that will be introduced in Section 8.4.1. In that case, uncertainty will be explicitly modeled. The resulting formulation and concepts can be considered as an extension of this section.