ON THE CONVEXITY OF A CUBIC B(?)ZIER CURVE
关于三次Bézier曲线的凸性

This paper is a supplement to 1]. The cubic Bezier curve is called convex if ithas neither inflection point, double point nor cusp. Necessary and sufficient conditionsfor the convexity of a cubic Bezier curve are obtained and the geometrical significancesof these conditions are added.