Definition:Positive Real Function

Definition
Let $I$ be a real interval.

Let $f$ be a real function.

Then $f$ is positive (on $I$) :
 * $\forall x \in I: f \left({x}\right) \ge 0$

Also known as
A positive real function is also described as non-negative in order to avoid confusing with a strictly positive real function.

Also see

 * Definition:Strictly Positive Real Function


 * Definition:Negative Real Function
 * Definition:Strictly Negative Real Function