I believe that this is wrong.Originally Posted bykodirl

p nand q= -(p^q)=-p v -q (By de Morgan's laws).

You cannot conclude that,

-p v -q = -p

Unless -q is false, i.e. q is true.

(p nand p) nand (q nand q) = -[(p nand p) ^ (q nand q)]Originally Posted bykodirl

=-(p nand p) v -(q nand q)=-[-(p ^ p)] v -[-(q ^ q)]

=(p^p) v (q^q)=p v q