问答题 设A={a,b},B={0,1,2},计算BA={f|f:A→B}.
【正确答案】BA={f1,f2,…,f9},其中:
   f1={〈a,0〉,〈b,0〉},  f2={〈a,0〉,〈b,1〉},  f3={〈a,0〉,〈b,2〉},
   f4={〈a,1〉,〈b,0〉},  f5={〈a,1〉,〈b,1〉},f6={〈a,1〉,〈b,2〉},
   f7={〈a,2〉,〈b,0〉},  f8={〈a,2〉,〈b,1〉}, f9={〈a,2〉,〈b,2〉}.
【答案解析】