Mathematical Models
Mathematical models relate decision variables (or controllable inputs) with fixed or variable parameters (or uncontrollable inputs).
Frequently mathematical models seek to maximize or minimize some objective function subject to constraints.
If any of the uncontrollable inputs is subject to variation the model is said to be stochastic; otherwise the model is said to be deterministic.
Generally, stochastic models are more difficult to analyze.
The values of the decision variables that provide the mathematically-best output are referred to as the optimal solution for the model.