The dyadic Boolean operation whose result has the Boolean value 0 if and only if the first operand has the Boolean value 0 and the second has the Boolean value 1.

• 一种二元布尔运算,在这种运算中,当且仅当第一个操作数的布尔值为0,第二个操作数的布尔值为1时,其结果的布尔值才为0。