问一道离散数学题
问题描述：
问一道离散数学题
If f og is one-to-one,does it follow that g is one-to-one?explain
答
yes. 否则,如果存在不相等的 x1,x2 使得 g(x1)=g(x2）则 f(g(x1)=f（g(x2)). 则 f og is NOT one-to-one. 矛盾!