设A ={a,b,c,d},B = {1,2,3,4},A到B的关系R = {, , } ,B到A的关系s = {, , },则
= __________
{,
设A ={a,b,c,d},B = {1,2,3,4},A到B的关系R = {, , } ,B到A的关系s = {, , },则
= __________
设A ={a,b,c,d},B = {1,2,3,4},A到B的关系R = {, , } ,B到A的关系s = {, , },则
= __________
{,