数学附录 7凸集: a set Xc界 n is said to be a convex set if for any two points xand x"in X and any real numberλ∈[0,1 the point x2=(1-x2+x”is contained in X. The intersection of any number of convex set is also convex 8. For any m points x),..., x m in Rn, and any 1min[0,1] such that∑入=1,x=∑入 x: is said to be a convex combination of x),.X数学附录 • ７ 凸集：A set Xn is said to be a convex set if for any two points x’ and x” in X and any real number [0, 1], the point x =(1-)x’+x” is contained in X. The intersection of any number of convex set is also convex. • ８. For any m points x1 ,…,xm in n , and any 1 ,…,m in [0, 1] such that ii=1, x=iixi is said to be a convex combination of x1 ,…,xm