Chapter 1.3, Problem 67E

We now present a group of exercises that involve the logical operatorsNANDandNOR. The propositionp NAND q, is true when eitherporq, or both, are false; and it is false when bothpandqare true. The propositionp NOR qis true when bothpandqare false, and it is false otherwise. The propositionsp NAND qandp NOR qare denoted by $p|q$

$p\downarrow q$, respectively. (The operators |and $\downarrow$are called theSheffer strokeand thePeirce arrowafter H. M. Sheffer and C. S. Peirce, respectively.)

67. Find the compound proposition Q constructed inExample 10for then-queens problem, and use it to find all the ways thatnqueens can be placed on an $n\times n$chessboard, so the no can attack another whennis

a) 2.

b) 3.

c) 4.