Definition:Decreasing/Real Function

Definition
This definition continues to hold when $S = T = \R$.

Thus, let $f$ be a real function.

Then $f$ is decreasing :
 * $x \le y \implies \map f y \le \map f x$.

Also see

 * Definition:Strictly Decreasing Real Function
 * Definition:Increasing Real Function
 * Definition:Monotone Real Function