See CARNAP.IO for a free, college intermediate level course on symbolic logic, both propositional and predicate. See LOGICAL RULES AND NOTATION for a general summary of the meanings of the proofs below. Some of the rules below are derived. Their proofs can also be found there as well. You can use the CARNAP.IO RULE BUILDERS to use these derivatives on their site. See this LOGIC CHEAT SHEET for things to keep in mind when trying to interpret statements logically, and then how to generally approach trying to prove them logically. There are generally a myriad of ways to conduct a proof. Below are merely some of the most concise ways I could think of. While these are valid proofs, I post them only for reference. Your use of them perhaps elsewhere as your own is on your own conscience. My aim is to give ways to look at the various problems in hope that seeing even a skeleton of an approach is enough to complete the thought in the person looking at these for reference. POSSIBLE SOLUTIONS
4.1 P .: P 1. SHOW: P 2. P :PR 3. :DD 2

4.2 P, (P->(P->Q)) .: Q 1. SHOW: Q 2. P :PR 3. P->(P->Q) :PR 4. P->Q :MP 2 3 5. Q :MP 2 4 6. :DD 5

4.3 P, Q, (P->(Q->R)) .: R 1. SHOW: R 2. P :PR 3. Q :PR 4. P->(Q->R) :PR 5. Q->R :MP 2 4 6. R :MP 3 5 7. :DD 6

4.4 ~P, (~Q->P) .: Q 1. SHOW: Q 2. ~P :PR 3. ~Q->P :PR 4. ~~Q :MT 2 3 5. Q :DNE 4 6. :DD 5

4.5 P, (~Q->~P) .: Q 1. SHOW: Q 2. P :PR 3. ~Q->~P :PR 4. ~~P :DNI 2 5. ~~Q :MT 3 4 6. Q :DNE 5 7. :DD 6

5.1 T .: (P->P) 1. SHOW: P->P 2. P :AS 3. :CD 2

5.2 Q .: (P->Q) 1. SHOW: P->Q 2. P :AS 3. Q :PR 4. :CD 3

5.3 P .: ((P->Q)->Q) 1. SHOW: (P->Q)->Q 2. P->Q :AS 3. P :PR 4. Q :MP 2 3 5. :CD 4

5.4 (P->Q), (Q->R) .: (P->R) 1. SHOW: P->R 2. P :AS 3. P->Q :PR 4. Q->R :PR 5. Q :MP 2 3 6. R :MP 4 5 7. :CD 6

5.5 (P->(P->Q)) .: (P->Q) 1. SHOW: P->Q 2. P :AS 3. P->(P->Q) :PR 4. P->Q :MP 2 3 5. Q :MP 2 4 6. :CD 5

5.6 T .: (~~P->P) 1. SHOW: ~~P->P 2. ~~P :AS 3. P :DNE 2 4. :CD 3

5.7 (P->Q) .: (~Q->~P) 1. SHOW: ~Q->~P 2. ~Q :AS 3. P->Q :PR 4. ~P :MT 2 3 5. :CD 4

5.8 (~Q->~P) .: (P->Q) 1. SHOW: P->Q 2. P :AS 3. ~Q->~P :PR 4. ~~P :DNI 2 5. ~~Q :MT 3 4 6. Q :DNE 5 7. :CD 6

5.9 (Q->P) .: (~~Q->P) 1. SHOW: ~~Q->P 2. ~~Q :AS 3. Q->P :PR 4. Q :DNE 2 5. P :MP 3 4 6. :CD 5

5.10 (P->~Q), (R->Q) .: (P->~R) 1. SHOW: P->~R 2. P :AS 3. P->~Q :PR 4. R->Q :PR 5. ~Q :MP 2 3 6. ~R :MT 4 5 7. :CD 6

6.1 T .: (P->(Q->P)) 1. SHOW: P->(Q->P) 2. P :AS 3. SHOW: Q->P 4. Q :AS 5. :CD 2 6. :CD 3

6.2 (P->Q) .: ((Q->R)->(P->R)) 1. SHOW: (Q->R)->(P->R) 2. Q->R :AS 3. SHOW: P->R 4. P :AS 5. P->Q :PR 6. Q :MP 4 5 7. R :MP 2 6 8. :CD 7 9. :CD 3

6.3 (P->(Q->R)) .: ((P->Q)->(P->R)) 1. SHOW: (P->Q)->(P->R) 2. P->Q :AS 3. SHOW: P->R 4. P :AS 5. P->(Q->R) :PR 6. Q->R :MP 4 5 7. Q :MP 2 4 8. R :MP 6 7 9. :CD 8 10. :CD 3

6.4 (P->(Q->R)) .: (Q->(P->R)) 1. SHOW: Q->(P->R) 2. Q :AS 3. SHOW: P->R 4. P :AS 5. P->(Q->R) :PR 6. Q->R :MP 4 5 7. R :MP 2 6 8. :CD 7 9. :CD 3

6.5 ((S->R)->Q), R .: Q 1. SHOW: Q 2. (S->R)->Q :PR 3. SHOW: S->R 4. S :AS 5. R :PR 6. :CD 5 7. Q :MP 2 3 8. :DD 7

7.1 (~P->P) .: ~~P 1. SHOW: ~~P 2. ~P :AS 3. ~P->P :PR 4. ~~P :MT 2 3 5. P :DNE 4 6. :ID 2 5

7.2 P, ~P .: ~Q 1. SHOW: ~Q 2. Q :AS 3. P :PR 4. ~P :PR 5. :ID 3 4

7.3 (~Q->R), (S->~R), (~S->Q) .: ~~Q 1. SHOW: ~~Q 2. ~Q :AS 3. ~Q->R :PR 4. S->~R :PR 5. ~S->Q :PR 6. R :MP 2 3 7. ~~R :DNI 6 8. ~S :MT 4 7 9. Q :MP 5 8 10. ~~Q :DNI 9 11. :ID 2 10

7.4 (P->Q), (Q->R), (R->S), P .: ~(P->~S) 1. SHOW: ~(P->~S) 2. P->~S :AS 3. P->Q :PR 4. Q->R :PR 5. R->S :PR 6. P :PR 7. ~S :MP 2 6 8. Q :MP 3 6 9. R :MP 4 8 10. S :MP 5 9 11. :ID 7 10

7.5 ((P->Q)->R), (S->(P->Q)), (~S->R) .: ~~R 1. SHOW: ~~R 2. ~R :AS 3. (P->Q)->R :PR 4. S->(P->Q) :PR 5. ~S->R :PR 6. ~(P->Q) :MT 2 3 7. ~~S :MT 2 5 8. S :DNE 7 9. P->Q :MP 4 8 10. :ID 6 9

7.6 (~P->(R->S)), ((R->S)->T), ~T, (Q->(R->S)) .: ~(P->Q) 1. SHOW: ~(P->Q) 2. P->Q :AS 3. ~P->(R->S) :PR 4. (R->S)->T :PR 5. ~T :PR 6. Q->(R->S) :PR 7. ~(R->S) :MT 4 5 8. ~~P :MT 3 7 9. P :DNE 8 10. Q :MP 2 9 11. R->S :MP 6 10 12. :ID 7 11

7.7 T .: ((~P->P)->~~P) 1. SHOW: (~P->P)->~~P 2. ~P->P :AS 3. SHOW: ~~P 4. ~P :AS 5. P :MP 2 4 6. :ID 4 5 7. :CD 3

7.8 (R->(Q->P)), (Q->~P) .: (R->~Q) 1. SHOW: R->~Q 2. R :AS 3. SHOW: ~Q 4. Q :AS 5. R->(Q->P) :PR 6. Q->~P :PR 7. Q->P :MP 2 5 8. ~P :MP 4 6 9. P :MP 4 7 10. :ID 8 9 11. :CD 3

7.9 (P->Q), (Q->R), (R->S) .: (P->~(P->~S)) 1. SHOW: P->~(P->~S) 2. P :AS 3. SHOW: ~(P->~S) 4. P->~S :AS 5. P->Q :PR 6. Q->R :PR 7. R->S :PR 8. ~S :MP 2 4 9. ~R :MT 7 8 10. ~Q :MT 6 9 11. ~P :MT 5 10 12. :ID 2 11 13. :CD 3

7.10 (P->Q), ((R->Q)->~P) .: ~P 1. SHOW: ~P 2. P :AS 3. P->Q :PR 4. (R->Q)->~P :PR 5. SHOW: R->Q 6. R :AS 7. Q :MP 2 3 8. :CD 7 9. ~P :MP 4 5 10. :ID 2 9

8.1 (P->Q), (Q->R), ((P->R)->(U->S)), (S->T) .: (U->T) 1. SHOW: U->T 2. U :AS 3. SHOW: P->R 4. P :AS 5. P->Q :PR 6. Q :MP 4 5 7. Q->R :PR 8. R :MP 6 7 9. :CD 8 10. (P->R)->(U->S) :PR 11. U->S :MP 3 10 12. S :MP 2 11 13. S->T :PR 14. T :MP 12 13 15. :CD 14

8.2 (P->(P->R)), ((P->R)->R) .: R 1. SHOW: R 2. (P->R)->R :PR 3. SHOW: P->R 4. P :AS 5. P->(P->R) :PR 6. P->R :MP 4 5 7. R :MP 4 6 8. :CD 7 9. R :MP 2 3 10. :DD 9

8.3 T, ((R->T)->~Q), ((Q->S)->W) .: W 1. SHOW: W 2. SHOW:R->T 3. R :AS 4. T :PR 5. :CD 4 6. (R->T)->~Q :PR 7. ~Q :MP 2 6 8. SHOW: Q->S 9. Q :AS 10. S :EFQ 7 9 11. :CD 10 12. (Q->S)->W :PR 13. W :MP 8 12 14. :DD 13

8.4 (P->~(S->W)), W .: (P->(Q->R)) 1. SHOW: P->(Q->R) 2. P :AS 3. P->~(S->W) :PR 4. ~(S->W) :MP 2 3 5. S/\~W :NCND_1 4 6. ~W :S 5 7. W :PR 8. Q->R :EFQ 6 7 9. :CD 8

8.5 T .: (S->((~P->~Q)->(Q->P))) 1. SHOW: S->((~P->~Q)->(Q->P)) 2. S :AS 3. SHOW: (~P->~Q)->(Q->P) 4. ~P->~Q :AS 5. SHOW: Q->P 6. Q :AS 7. ~~Q :DNI 6 8. ~~P :MT 4 7 9. P :DNE 8 10. :CD 9 11. :CD 5 12. :CD 3

8.6 ((R->S)->~P), (Q->T), (~Q->(R->S)), (T->(U->V)) .: (P->(~V->~U)) 1. SHOW: P->(~V->~U) 2. P :AS 3. ~Q->(R->S) :PR 4. (R->S)->~P :PR 5. Q->T :PR 6. T->(U->V) :PR 7. ~Q->~P :HS 3 4 8. Q->(U->V) :HS 5 6 9. P->Q :CONP_2 7 10. P->(U->V) :HS 8 9 11. U->V :MP 2 10 12. ~V->~U :CONP_1 11 13. :CD 12

8.7 (P->R), (R->~Q), (S->P), (Q->S) .: ~Q 1. SHOW: ~Q 2. P->R :PR 3. R->~Q :PR 4. S->P :PR 5. Q->S :PR 6. Q->P :HS 4 5 7. P->~Q :HS 2 3 8. ~P->~Q :CONP_1 6 9. ~Q :DIL 7 8 10. :DD 9

8.8 (~Q->~~P), (~~R->~Q), (~R->P) .: P 1. SHOW: P 2. ~R->P :PR 3. ~~R->~Q :PR 4. ~Q->~~P :PR 5. ~~R->~~P :HS 3 4 6. ~P->~R :CONP_2 5 7. R->P :CONP_2 6 8. P :DIL 2 7 9. :DD 8

8.9 (P->~P), (R->P), (Q->R), (~Q->R) .: S 1. SHOW: S 2. P->~P :PR 3. R->P :PR 4. Q->R :PR 5. ~Q->R :PR 6. Q->P :HS 3 4 7. ~Q->P :HS 3 5 8. P :DIL 6 7 9. ~P :MP 2 8 10. S :EFQ 8 9 11. :DD 10

8.10 T .: (((P->Q)->P)->P) 1. SHOW: ((P->Q)->P)->P 2. (P->Q)->P :AS 3. SHOW: ~~P 4. ~P :AS 5. ~(P->Q) :MT 2 4 6. P->Q :CND_2 4 7. :ID 5 6 8. P :DNE 3 9. :CD 8

9.1 (P/\Q) .: (P v Q) 1. SHOW: P v Q 2. P/\Q :PR 3. P :S 2 4. P v Q :ADD 3 5. :DD 4

9.2 T .: ~(P/\~P) 1. SHOW: ~(P/\~P) 2. P/\~P :AS 3. P :S 2 4. ~P :S 2 5. :ID 3 4

9.3 ~Q .: ~(P/\Q) 1. SHOW: ~(P/\Q) 2. P/\Q :AS 3. ~Q :PR 4. Q :S 2 5. :ID 3 4

9.4 1. SHOW: ~(P v Q) 2. P v Q :AS 3. ~P :PR 4. ~Q :PR 5. ~P/\~Q :ADJ 3 4 6. Q :MTP 2 3 7. :ID 4 6

9.5 ~(P v Q) .: ~P 1. SHOW: ~P 2. P :AS 3. ~(P v Q) :PR 4. P v Q :ADD 2 5. :ID 3 4

9.6 T .: ((P/\Q)<->(Q/\P)) 1. SHOW: (P/\Q)<->(Q/\P) 2. SHOW: (P/\Q)->(Q/\P) 3. P/\Q :AS 4. SHOW: Q/\P 5. Q :S 3 6. P :S 3 7. Q/\P :ADJ 5 6 8. :DD 7 9. :CD 4 10. SHOW: (Q/\P)->(P/\Q) 11. Q/\P :AS 12. SHOW: P/\Q 13. P :S 11 14. Q :S 11 15. P/\Q :ADJ 13 14 16. :DD 15 17. :CD 12 18. (P/\Q)<->(Q/\P) :CB 2 10 19. :DD 18

9.7 (P v ~Q), (Q v R), ~P .: R 1. SHOW: R 2. P v ~Q :PR 3. Q v R :PR 4. ~P :PR 5. ~Q :MTP 2 4 6. R :MTP 3 5 7. :DD 6

9.8 ((P/\Q)->R) .: ((P/\~R)->~Q) 1. SHOW: (P/\~R)->~Q 2. P/\~R :AS 3. SHOW: ~Q 4. Q :AS 5. (P/\Q)->R :PR 6. P :S 2 7. P/\Q :ADJ 4 6 8. R :MP 5 7 9. ~R :S 2 10. :ID 8 9 11. :CD 3

9.9 ((P/\~R)->~Q) .: ((P/\Q)->R) 1. SHOW: (P/\Q)->R 2. P/\Q :AS 3. SHOW: ~~R 4. ~R :AS 5. (P/\~R)->~Q :PR 6. P :S 2 7. P/\~R :ADJ 4 6 8. ~Q :MP 5 7 9. Q :S 2 10. :ID 8 9 11. R :DNE 3 12. :CD 11

9.10 (P->Q) .: ((P/\R)->(Q/\R)) 1. SHOW: (P/\R)->(Q/\R) 2. P/\R :AS 3. SHOW: Q/\R 4. Q :AS 5. R :S 2 6. Q/\R :ADJ 4 5 7. :CD 6 8. :CD 3

11.6 ~(~P->(Q/\R)), (~S v P) .: ~S 1. SHOW: ~S 2. ~(~P->(Q/\R)) :PR 3. ~S v P :PR 4. ~P/\~(Q/\R) :NCND_1 2 5. ~P :S 4 6. ~S :MTP 3 5 7. :DD 6

11.7 ((P v Q)->S), ~(R v ~P) .: ~(R<->S) 1. SHOW: ~(R<->S) 2. R<->S :AS 3. (P v Q)->S :PR 4. ~(R v ~P) :PR 5. ~R/\~~P :DM_2 4 6. ~~P :S 5 7. P :DNE 6 8. P v Q :ADD 7 9. ~R :S 5 10. S :MP 3 8 11. S->R :BC 2 12. R :MP 10 11 13. :ID 9 12

11.8 ((P->Q)->T), (S v T), (P->(S->Q)) .: T 1. SHOW: T 2. SHOW: ~~T 3. ~T :AS 4. (P->Q)->T :PR 5. S v T :PR 6. P->(S->Q) :PR 7. S :MTP 3 5 8. ~(P->Q) :MT 3 4 9. P/\~Q :NCND_1 8 10. P :S 9 11. S->Q :MP 6 10 12. Q :MP 7 11 13. ~Q :S 9 14. :ID 12 13 15. T :DNE 2 16. :DD 15

11.9 ((P->Q)->P), (Q->P) .: P 1. SHOW: P 2. SHOW: ~~P 3. ~P :AS 4. (P->Q)->P :PR 5. P->Q :CND_2 3 6. ~(P->Q) :MT 3 4 7. :ID 5 6 8. P :DNE 2 9. :DD 8

11.10 ~(P->Q), ~(R->Q) .: ~(P->~R) 1. SHOW: ~(P->~R) 2. P->~R :AS 3. ~(P->Q) :PR 4. ~(R->Q) :PR 5. P/\~Q :NCND_1 3 6. R/\~Q :NCND_1 4 7. P :S 5 8. R :S 6 9. ~R :MP 2 7 10. :ID 8 9

12.1 (P<->S), (~Q->~P), (~R->P) .: (R v (S/\Q)) 1. SHOW: R v (S/\Q) 2. SHOW: ~~(R v (S/\Q)) 3. ~(R v (S/\Q)) :AS 4. ~R/\~(S/\Q) :DM_2 3 5. ~R :S 4 6. ~(S/\Q) :S 4 7. P<->S :PR 8. ~Q->~P :PR 9. ~R->P :PR 10. P :MP 5 9 11. ~S v ~Q :DM_4 6 12. ~~P :DNI 10 13. ~~Q :MT 8 12 14. ~S :MTP 11 13 15. P->S :BC 7 16. ~P :MT 14 15 17. :ID 10 16 18. R v (S/\Q) :DNE 2 19. :DD 18

12.2 (P v S), (S->~(Q->~P)) .: (P v R) 1. SHOW: P v R 2. SHOW: ~~P 3. ~P :AS 4. P v S :PR 5. S :MTP 3 4 6. S->~(Q->~P) :PR 7. ~(Q->~P) :MP 5 6 8. Q/\~~P :NCND_1 7 9. ~~P :S 8 10. :ID 3 9 11. P :DNE 2 12. P v R :ADD 11 13. :DD 12

13.9 T .: (((P->R)/\(Q->S))->((P/\Q)->(R/\S))) 1. SHOW: ((P->R)/\(Q->S))->((P/\Q)->(R/\S)) 2. (P->R)/\(Q->S) :AS 3. SHOW: (P/\Q)->(R/\S) 4. P/\Q :AS 5. P :S 4 6. Q :S 4 7. P->R :S 2 8. Q->S :S 2 9. R :MP 5 7 10. S :MP 6 8 11. R/\S :ADJ 9 10 12. :CD 11 13. :CD 3

13.10 T .: ((P->(Q<->R))<->((P/\Q)<->(P/\R))) 1. SHOW: (P->(Q<->R))<->((P/\Q)<->(P/\R)) 2. SHOW: (P->(Q<->R))->((P/\Q)<->(P/\R)) 3. P->(Q<->R) :AS 4. SHOW: (P/\Q)<->(P/\R) 5. SHOW: (P/\Q)->(P/\R) 6. P/\Q :AS 7. P :S 6 8. Q :S 6 9. Q<->R :MP 3 7 10 Q->R :BC 9 11. R :MP 8 10 12. P/\R :ADJ 7 11 13. :CD 12 14. SHOW: (P/\R)->(P/\Q) 15. P/\R :AS 16. P :S 15 17. R :S 15 18. Q<->R :MP 3 16 19. R->Q :BC 18 20. Q :MP 17 19 21. P/\Q :ADJ 16 20 22. :CD 21 23. (P/\Q)<->(P/\R) :CB 5 14 24. :DD 23 25. :CD 4 26. SHOW: ((P/\Q)<->(P/\R))->(P->(Q<->R)) 27. (P/\Q)<->(P/\R) :AS 28. (P/\Q)->(P/\R) :BC 27 29. (P/\R)->(P/\Q) :BC 27 30. SHOW: P->(Q<->R) 31. P :AS 32. SHOW: Q->R 33. Q :AS 34. P/\Q :ADJ 31 33 35. P/\R :MP 28 34 36. R :S 35 37. :CD 36 38. SHOW: R->Q 39. R :AS 40. P/\R :ADJ 31 39 41. P/\Q :MP 29 40 42. Q :S 41 43. :CD 42 44. (Q<->R) :CB 32 38 45. :CD 44 46. :CD 30 47. (P->(Q<->R))<->((P/\Q)<->(P/\R)) :CB 2 26 48. :DD 47

14.9 T .: (((P->Q) v R)<->(P->(Q v R))) 1. SHOW: ((P->Q) v R)<->(P->(Q v R)) 2. SHOW: ((P->Q) v R)->(P->(Q v R)) 3. (P->Q) v R :AS 4. SHOW: ~~(P->(Q v R)) 5. ~(P->(Q v R)) :AS 6. P/\~(Q v R) :NCND_1 5 7. ~(Q v R) :S 6 8. ~Q/\~R :DM_2 7 9. P :S 6 10. ~Q :S 8 11. ~(P->Q) :NCND_2 9 10 12. R :MTP 3 11 13. ~R :S 8 14. :ID 12 13 15. P->(Q v R) :DNE 4 16. :CD 15 17. SHOW: (P->(Q v R))->((P->Q) v R) 18. P->(Q v R) :AS 19. SHOW: ~~((P->Q) v R) 20. ~((P->Q) v R) :AS 21. ~(P->Q)/\~R :DM_2 20 22. ~(P->Q) :S 21 23. P/\~Q :NCND_1 22 24. P :S 23 25. ~Q :S 23 26. ~R :S 21 27. ~Q/\~R :ADJ 25 26 28. ~(Q v R) :DM_1 27 29. ~(P->(Q v R)) :NCND_2 24 28 30. :ID 18 29 31. (P->Q) v R :DNE 19 32. :CD 31 33. ((P->Q) v R)<->(P->(Q v R)) :CB 2 17 34. :DD 33

14.10 (P<->Q), (P<->R) .: (P<->(Q v R)) 1. SHOW: P<->(Q v R) 2. P<->Q :PR 3. P<->R :PR 4. P->Q :BC 2 5. Q->P :BC 2 6. R->P :BC 3 7. SHOW: P->(Q v R) 8. P :AS 9. Q :MP 4 8 10 Q v R :ADD 9 11. :CD 10 12. SHOW: (Q v R)->P 13. Q v R :AS 14. P :CASES 5 6 13 15. :CD 14 16. P<->(Q v R) :CB 7 12 17. :DD 16

16.1 Ax(F(x)/\G(x)) .: F(c) 1. SHOW: F(c) 2. Ax(F(x)/\G(x)) :PR 3. F(c)/\G(c) :UI 2 4. F(c) :S 3 5. :DD 4

16.2 AxF(x), (F(c)->G(c)) .: G(c) 1. SHOW: G(c) 2. AxF(x) :PR 3. F(c)->G(c) :PR 4. F(c) :UI 2 5. G(c) :MP 3 4 6. :DD 5

16.3 AxF(x), ((F(b)/\F(c))->G(c)) .: ExG(x) 1. SHOW: ExG(x) 2. AxF(x) :PR 3. (F(b)/\F(c))->G(c) :PR 4. F(b) :UI 2 5. F(c) :UI 2 6. F(b)/\F(c) :ADJ 4 5 7. G(c) :MP 3 6 8. ExG(x) :EG 7 9. :DD 8

16.4 AxAy(F(x)->G(y)), F(c) .: G(d) 1. SHOW: G(d) 2. AxAy(F(x)->G(y)) :PR 3. F(c) :PR 4. Ay(F(c)->G(y)) :UI 2 5. F(c)->G(d) :UI 4 6. G(d) :MP 3 5 7. :DD 6

16.5 AxAy(F(x)<->G(y)), F(c) .: F(d) 1. SHOW: F(d) 2. AxAy(F(x)<->G(y)) :PR 3. F(c) :PR 4. Ay(F(c)<->G(y)) :UI 2 5. Ay(F(d)<->G(y)) :UI 2 6. F(c)<->G(d) :UI 4 7. F(d)<->G(d) :UI 5 8. F(c)->G(d) :BC 6 9. G(d)->F(d) :BC 7 10. F(c)->F(d) :HS 8 9 11. F(d) :MP 3 10 12. :DD 11

17.1 Ax(F(x)->G(x)), AxF(x) .: AxG(x) 1. SHOW: AxG(x) 2. Ax(F(x)->G(x)) :PR 3. AxF(x) :PR 4. F(c)->G(c) :UI 2 5. F(c) :UI 3 6. G(c) :MP 4 5 7. :UD 6

17.2 Ax(F(x)->G(x)), Ax(G(x)->H(x)) .: Ax(F(x)->H(x)) 1. SHOW: Ax(F(x)->H(x)) 2. Ax(F(x)->G(x)) :PR 3. Ax(G(x)->H(x)) :PR 4. F(c)->G(c) :UI 2 5. G(c)->H(c) :UI 3 6. F(c)->H(c) :HS 4 5 7. :UD 6

17.3 Ax(G(x)/\G(c)) .: AxG(x) 1. SHOW: AxG(x) 2. Ax(G(x)/\G(c)) :PR 3. G(a)/\G(c) :UI 2 4. G(a) :S 3 5. :UD 4

17.4 Ax~F(x), F(d) .: ~AxF(x) 1. SHOW: ~AxF(x) 2. Ax~F(x) :PR 3. F(d) :PR 4. ~F(d) :UI 2 5. ~AxF(x) :EFQ 3 4 6. :DD 5

17.5 ~ExF(x) .: Ax~F(x) 1. SHOW: Ax~F(x) 2. ~ExF(x) :PR 3. Ax~F(x) :QN_1 2 4. :DD 3

17.6 Ex(F(x)/\G(a)) .: G(a) 1. SHOW: G(a) 2. Ex(F(x)/\G(a)) :PR 3. SHOW: G(a) 4. F(b)/\G(a) :AS 5. G(a) :S 4 6. :ED 2 4 5 7. :DD 3

17.7 Ax(F(x)->G(x)), ExF(x) .: ExG(x) 1. SHOW: ExG(x) 2. Ax(F(x)->G(x)) :PR 3. ExF(x) :PR 4. SHOW: ExG(x) 5. F(c) :AS 6. F(c)->G(c) :UI 2 7. G(c) :MP 5 6 8. ExG(x) :EG 7 9. :ED 3 5 8 10. :DD 4

17.8 Ax(F(x)->G(x)), Ex(F(x)/\H(x)) .: Ex(G(x)/\H(x)) 1. SHOW: Ex(G(x)/\H(x)) 2. Ax(F(x)->G(x)) :PR 3. Ex(F(x)/\H(x)) :PR 4. SHOW: Ex(G(x)/\H(x)) 5. F(c)/\H(c) :AS 6. F(c)->G(c) :UI 2 7. F(c) :S 5 8. H(c) :S 5 9. G(c) :MP 6 7 10. G(c)/\H(c) :ADJ 8 9 11. Ex(G(x)/\H(x)) :EG 10 12. :ED 3 5 11 13. :DD 4

17.9 Ax(F(x)->G(x)), ~Ex(F(x)/\G(x)) .: ~ExF(x) 1. SHOW: ~ExF(x) 2. Ax(F(x)->G(x)) :PR 3. ~Ex(F(x)/\G(x)) :PR 4. SHOW: ~ExF(x) 5. ExF(x) :AS 6. SHOW: Ex(F(x)/\G(x)) 7. F(c) :AS 8. F(c)->G(c) :UI 2 9. G(c) :MP 7 8 10 F(c)/\G(c) :ADJ 7 9 11. Ex(F(x)/\G(x)) :EG 10 12. :ED 5 7 11 13. :ID 3 6 14. :DD 4

17.10 Ex~F(x) .: ~AxF(x) 1. SHOW: ~AxF(x) 2. Ex~F(x) :PR 3. SHOW: ~AxF(x) 4. AxF(x) :AS 5. F(x) :UI 4 6. ExF(x) :EG 5 7. SHOW: ~ExF(x) 8. ~F(x) :AS 9. ~ExF(x) :EFQ 5 8 10. :ED 2 8 9 11. :ID 6 7 12. :DD 3

0.1 Ax(F(x)->G(x)), Ex(H(x)/\~G(x)) .: Ex(H(x)/\~F(x)) 1. SHOW: Ex(H(x)/\~F(x)) 2. Ax(F(x)->G(x)) :PR 3. Ex(H(x)/\~G(x)) :PR 4. SHOW: Ex(H(x)/\~F(x)) 5. H(x)/\~G(x) :AS 6. F(x)->G(x) :UI 2 7. H(x) :S 5 8. ~G(x) :S 5 9. ~F(x) :MT 6 8 10. H(x)/\~F(x) :ADJ 7 9 11. Ex(H(x)/\~F(x)) :EG 10 12. :ED 3 5 11 13. :DD 4

0.2 Ex(F(x)/\~G(x)), Ax(F(x)->H(x)) .: Ex(H(x)/\~G(x)) 1. SHOW: Ex(H(x)/\~G(x)) 2. Ex(F(x)/\~G(x)) :PR 3. Ax(F(x)->H(x)) :PR 4. SHOW: Ex(H(x)/\~G(x)) 5. F(x)/\~G(x) :AS 6. F(x)->H(x) :UI 3 7. F(x) :S 5 8. H(x) :MP 6 7 9. ~G(x) :S 5 10. H(x)/\~G(x) :ADJ 8 9 11. Ex(H(x)/\~G(x)) :EG 10 12. :ED 2 5 11 13. :DD 4

0.3 Ax(F(x)->G(x)), ~Ex(G(x)/\H(x)) .: ~Ex(H(x)/\F(x)) 1. SHOW: ~Ex(H(x)/\F(x)) 2. Ex(H(x)/\F(x)) :AS 3. Ax(F(x)->G(x)) :PR 4. ~Ex(G(x)/\H(x)) :PR 5. SHOW: Ex(G(x)/\H(x)) 6. H(x)/\F(x) :AS 7. F(x)->G(x) :UI 3 8. H(x) :S 6 9. F(x) :S 6 10. G(x) :MP 7 9 11. G(x)/\H(x) :ADJ 8 10 12. Ex(G(x)/\H(x)) :EG 11 13. :ED 2 6 12 14. :ID 4 5

0.4 Ax(H(x)->F(x)), ~Ex(F(x)/\G(x)) .: ~Ex(H(x)/\G(x)) 1. SHOW: ~Ex(H(x)/\G(x)) 2. Ex(H(x)/\G(x)) :AS 3. Ax(H(x)->F(x)) :PR 4. ~Ex(F(x)/\G(x)) :PR 5. SHOW: Ex(F(x)/\G(x)) 6. H(x)/\G(x) :AS 7. H(x)->F(x) :UI 3 8. H(x) :S 6 9. F(x) :MP 7 8 10. G(x) :S 6 11. F(x)/\G(x) :ADJ 9 10 12. Ex(F(x)/\G(x)) :EG 11 13. :ED 2 6 12 14. :ID 4 5

0.5 ~Ex(F(x)/\G(x)), Ex(H(x)/\F(x)) .: Ex(H(x)/\~G(x)) 1. SHOW: Ex(H(x)/\~G(x)) 2. ~Ex(F(x)/\G(x)) :PR 3. Ex(H(x)/\F(x)) :PR 4. Ax~(F(x)/\G(x)) :QN_1 2 5. SHOW: Ex(H(x)/\~G(x)) 6. H(x)/\F(x) :AS 7. ~(F(x)/\G(x)) :UI 4 8. ~F(x) v ~G(x) :DM_4 7 9. F(x) :S 6 10. ~~F(x) :DNI 9 11. H(x) :S 6 12. ~G(x) :MTP 8 10 13. H(x)/\~G(x) :ADJ 11 12 14. Ex(H(x)/\~G(x)) :EG 13 15. :ED 3 6 14 16. :DD 5

0.6 T .: (Ax(F(x)/\G(x)))<->(AxF(x)/\AxG(x)) 1. SHOW: (Ax(F(x)/\G(x)))<->(AxF(x)/\AxG(x)) 2. SHOW: Ax(F(x)/\G(x))->(AxF(x)/\AxG(x)) 3. Ax(F(x)/\G(x)) :AS 4. F(x)/\G(x) :UI 3 5. SHOW: AxF(x) 6. F(x) :S 4 7. :UD 6 8. SHOW: AxG(x) 9. G(x) :S 4 10. :UD 9 11. AxF(x)/\AxG(x) :ADJ 5 8 12. :CD 11 13. SHOW: (AxF(x)/\AxG(x))->Ax(F(x)/\G(x)) 14. AxF(x)/\AxG(x) :AS 15. AxF(x) :S 14 16. AxG(x) :S 14 17. F(x) :UI 15 18. G(x) :UI 16 19. SHOW: Ax(F(x)/\G(x)) 20. F(x)/\G(x) :ADJ 17 18 21. :UD 20 22. :CD 19 23. (Ax(F(x)/\G(x)))<->(AxF(x)/\AxG(x)) :CB 2 13 24. :DD 23

0.11 ExF(x)->ExG(x) .: Ex(F(x)-> G(x)) 1. SHOW: Ex(F(x)->G(x)) 2. SHOW: ~~Ex(F(x)->G(x)) 3. ~Ex(F(x)->G(x)) :AS 4. ExF(x)->ExG(x) :PR 5. Ax~(F(x)->G(x)) :QNONE 3 6. ~(F(c)->G(c)) :UI 5 7. F(c)/\~G(c) :NEGCONONE 6 8. F(c) :S 7 9. ExF(x) :EG 8 10. ExG(x) :MP 4 9 11. SHOW: Ex(F(x)->G(x)) 12. G(c) :AS 13. F(c)->G(c) :CONONE 12 14. Ex(F(x)->G(x)) :EG 13 15. :ED 10 12 14 16. :ID 3 11 17. Ex(F(x)->G(x)) :DNE 2 18. :DD 17