Definition:Midpoint-Concave

Definition
Let $f$ be a real function defined on a real interval $I$.

$f$ is midpoint-concave :
 * $\forall x, y \in I: f \left({\dfrac {x + y} 2}\right) \ge \dfrac {f \left({x}\right) + f \left({y}\right)} 2$

Also see

 * Definition:Strictly Midpoint-Concave


 * Definition:Midpoint-Convex
 * Definition:Strictly Midpoint-Convex