Duality Principle: Dual of an expression can be obtained by : Changing all + with . Complement 0’s and 1’s i.e. 1’=0 and 0’=1 Keep the variable sam (i.e. do not complement the variable) Example: Find the dual of : A(B+C) = AB + AC Solution: Find the Dual of F(xyz)=(x+y) (x+z)(y+z) Solution:             (x+y) (x+z)(y+z) =          (xx+xz+xy +yz)(y+z) =          (x+xz+xy+yz)(y+z) =          (x +xy +yz )(y+z) =          (x+yz)(y+z) =          xy +xz + yyz + yz =          xy + xz + yz Also dual of (x+y) (x+z)(y+z)  = xy + xz + yz Therefore, we find that in this case dual of a function is the function itself 3. For n variables expression haw many total dual functions are possible Solution: Which of the following is TRUE S1: The dual of NAND function is NOR S2:The dual of