Definition:Strictly Negative Real Function

Definition

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.

Also see

• Definition:Negative Real Function

• Definition:Positive Real Function
• Definition:Strictly Positive Real Function