Solution
= Solution
A <convex function> satisfies
$$
\boxed{F((1-t)x+ty)\leq(1-t)F(x)+tF(y)
\quad(x,y\in\mathbb R^n,\ 0\leq t\leq1).}
$$
Its value on a line segment never lies above the chord joining its endpoint values.
= Solution
A <convex function> satisfies
$$
\boxed{F((1-t)x+ty)\leq(1-t)F(x)+tF(y)
\quad(x,y\in\mathbb R^n,\ 0\leq t\leq1).}
$$
Its value on a line segment never lies above the chord joining its endpoint values.