THE POSITIVITY AND CONVEXITY FOR BERNSTEIN POLYNOMIALS OVER TRIANGLES
三角域上Bernstein多项式的正性与凸性

Explicit expressions of the coefficients of degree elevation of any order for theBernstein polynomial over triangles are presented. Based on these expressions, a ne-cessary and sufficient condition for the positivity of the polynomial and a similar con-dition for its strong convexity are established.