... XB∪XC∪XD | = ∑=−−411),4()1(kkkX= (-1 ) 1-1 X(4,1) + (-1 ) 2-1 X(4,2) + (-1 ) 3-1 X(4,3) + (-1 ) 4-1 X(4,4) = X(4,1) - X(4,2) + X(4,3) - X(4,4)= s1 – s2 + s3 – s4(*) => |X| ... ͞A4| = |A| - | A1∪ A2∪A3∪A4 |Trong đó: | A1∪ A2∪A3∪A4 | = ∑=−−411),4()1(kkkA= (-1 ) 1-1 A(4,1) + (-1 ) 2-1 A(4,2) + (-1 ) 3-1 A(4,3) + (-1 ) 4-1 A(4,4) = A(4,1) - A(4,2) ... ͞A1∩ ͞͞A2∩ ͞A3| = |A| - | A1∪ A2∪A3|Trong đó: | A1∪ A2∪A3 | = ∑=−−311),3()1(kkkA= (-1 ) 1-1 A(3,1) + (-1 ) 2-1 A(3,2) + (-1 ) 3-1 A(3,3) = A(3,1) - A(3,2) + A(3,3) = s1...