Convex Optimization, Convex Sets, Convex Function, Convex Hull, Convexity.
x1, x2 that also connect the arc, lies above the arc. Similar is the case with points x3 and x4. In fig.2, the same thing happens. The line segment joining points x1 and x2 lies above the function. On the other hand, line segment joining points x3 and x4 lies on the function. So, we can clearly see