# Prepositional Homework Stuck

• Dec 10th 2008, 06:14 PM
Slugger
Prepositional Homework Stuck
I am stuck on these problems.

• ((B v C) & -D) -> ((G-> -L) & P), P->(G&L) (-B v D) & (-C v D)

1 1. ((B v C) & -D) -> ((G-> -L) & P) A
2 2. P->(G&L) A
3 3. B PA
4 4. -D PA
5 5. C PA
6 6. -((-B v D) & (-C v D)) PA
3 7. B v C 3, vI
3,4 8. ((B v C) & -D) 4,7 &I
1,3,4 9. (G->-L) & P 1,8 ->O
1,3,4 10. P 9, &O
1,2,3,4 11. G&L 2,10 ->O
1,2,3,4 12. G->-L 9 &O
1,2,3,4 13. G 11 &O
1,2,3,4 14. L 11 &O
1,2,3,4 15. -L 12,13 ->O
1,2,3,4 16. L & -L 14,15 &I
1,2,4 17. ~B 3-16 –I
1,2,4 18. –B v D 17 vI
5 19. B v C 5 vI
4,5 20. ((B v C) & -D) 4,19 &I
1,4,5 21. (G->-L) & P 1,20 ->O
1,4,5 22. P 21, &O
1,2,4,5 23. G&L 2,22 ->O

And on this one I can't even figure out what to PA.

. -x(Px → yGxy) v x(Lx & Sx), -x(-Lx v –Sx) → (xy-Gxy→x-Px)
├ - ( ((x-Px v xyGxy) → -x(Lx → -Sx)) → ( x (Sx & Lx) & x(Px & y-Gxy) ) )
• Dec 10th 2008, 07:05 PM
Slugger
I figured out the first one, does anyone know the second one or at least what I should PA?