“若A={2,a-1,a2-3a-1},B={a+1,a+3,a2+2},当AIB={2,3}时,求a的值”中AIB是什么意思?

“若A={2,a-1,a2-3a-1},B={a+1,a+3,a2+2},当AIB={2,3}时,求a的值”中AIB是什么意思?
“若A={2,a-1,a2-3a-1},B={a+1,a+3,a2+2},当AIB={2,3}时,求a的值”中AIB是什么意思?

“若A={2,a-1,a2-3a-1},B={a+1,a+3,a2+2},当AIB={2,3}时,求a的值”中AIB是什么意思?
A∩B
就是A与B的交集是
{2,3}