# Definition:Strictly Positive Real Function

## Definition

Let $I$ be a real interval.

Let $f$ be a real function.

Then $f$ is strictly positive (on $I$) iff:

$\forall x \in I: f \left({x}\right) > 0$

## Also known as

A strictly positive real function is also described as a positive real function, but this causes confusion with a non-negative real function and so this usage is to be avoided.