Definition:Strictly Negative Real Function
Let $I$ be a real interval.
Let $f$ be a real function.
Then $f$ is strictly negative (on $I$) if and only if:
- $\forall x \in I: \map f x < 0$
Also known as
A strictly negative real function is also described as a negative real function, but this causes confusion with a non-positive real function and so this usage is to be avoided.