摘要
Slutsky定理指出:如果随机变量序列{X1n},{X2n},…,{Xmn}分别依概率收敛到m个有限常数a1,a2,…,am,那么任意一个有理函数R(X1n,X2n,…,Xmn)也依概率收敛到常数R(a1,a2,…,am),只要R(a1,a2,…,am)有限.本文从两个方面推广了这一结果:第一,若上述随机变量序列分别依概率收敛到随机变量X1,X2,…,Xm,g(x1,x2,…,xm)是m维欧氏空间Rm上的连续函数,则g(X1n,X2n,…,Xmn)依概率收敛于g(X1,X2,…,Xmn).第二,若上述随机变量序列分别收敛到m个有限常数a1,a2,…,am,又Borel可测函数g(x1,x2,…,xm)在点(a1,a2,…,am)处连续,则g(X1n,X2n,…,Xmn)依概率收敛到g(a1,a2,…,am).
In Slutsky′s theorem it is pointed out that if sequences of random variables {X1n},{X2n},…,{Xmn} converge to finite constants a1,a2,…,am in probability, respectively, then any rational function R(X1n,X2n,…,Xmn) also converges to constant R(a1,a2,…,am) as long as R(a1,a2,…,am) is finite We generalize Slutsky′s theorem in two aspects: (1) if the sequences of random variables mentioned above converge to random variables X1,X2,…,Xm in probability, and g(x1,x2,…,xm) is a continuous function on m-dimensional Eqclidean space, then g(X1n,X2n,…,Xmn) converges to g(X1,X2,…,Xmn) in probability, (2) if these sequences of random variables converge to finite constants a1,a2,…,am in probability, respectively, and Borel measurable function g(x1,x2,…,xm) is continuous at point (a1,a2,…,am) , then g(X1n,X2n,…,Xmn) converges to g(a1,a2,…,am) in probability