Strictly Convex

A set or a shape is strictly convex if, for any two points within it, the straight line connecting them lies entirely inside the shape, and this line only touches the boundary at the endpoints. In simple terms, a strictly convex shape has a smooth, rounded boundary with no flat edges or indentations—like a circle or an oval. This property ensures that there are no flat segments on its boundary, and the interior is "curved outward" at every point, which is important for certain mathematical and optimization problems.