مجموعه محدب

گوییم ${\displaystyle k\subset \mathbb {R} ^{n}}$

${\displaystyle k}$

${\displaystyle k}$

${\displaystyle {\tilde {x}}\in k}$

${\displaystyle {\hat {y}}\in k}$

${\displaystyle 0\leq \alpha \leq 1}$

${\displaystyle \alpha {\tilde {x}}+(1-\alpha ){\hat {y}}\in k}$