Extra PL Derivation Problems: Solutions

 

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1. DERIVE: ~Universal Quantifierx(~Fx v Gx )

1. Universal Quantifierx ( ~Fx v ~Gx ) PR
2. Fa PR
3.
| Universal Quantifierx( ~Fx v Gx )
AS
4.
| ~Fa v Ga
3 Universal QuantifierE
5.
| ~Fa v ~Ga
1 Universal QuantifierE
6.
| ~~Fa
2DN
7.
| Ga
4, 6 vE
8.
| ~Ga
5, 6 vE
9. ~Universal Quantifierx(~Fx v Gx ) 3-8 ~I

 

2. DERIVE: Existential QuantifierxGx

1 Universal Quantifierx( Fx Gx ) PR
2. Fm v Fn PR
3.
| ~Existential QuantifierxGx
AS
4.
|Universal Quantifierx~Gx
3 QN
5.
| Fm Gm
1 Universal QuantifierE
6.
| ~Gm
4 Universal QuantifierE
7.
| ~Fm
5,6 MT
8.
| Fn
2, 7 vE
9.
| Fn Gn
1 Universal QuantifierE
10.
| Gn
8,9 E
11.
| ~Gn
4 Universal QuantifierE
12. Existential QuantifierxGx 3-11 ~E

 

3. DERIVE: Existential Quantifierx( Fx & ~Gx )

1. Universal Quantifierx( Gx Existential Quantifiery~Kxy ) PR
2. Existential Quantifierx( Fx &Universal QuantifieryKxy ) PR
3. Fa &Universal QuantifieryKay 2 Existential QuantifierE
4. Ga Existential Quantifiery~Kay 1Universal QuantifierE
5. Universal QuantifieryKay 3 &E
6. ~~Universal QuantifieryKay 5 DN
7. ~Existential Quantifiery~Kay 6 QN
8. ~Ga 4, 7 MT
9. Fa 3 &E
10. Fa & ~Ga 8, 9 &I
11.  Existential Quantifierx( Fx & ~Gx ) 10 Existential QuantifierI

 

4. DERIVE: Universal Quantifierx( ~Fx & ~Hx ) Universal QuantifierxGx

1. Universal Quantifierx[( Fx Hx ) Gx ] PR
2.
| Universal Quantifierx( ~Fx & ~Hx )
AS
3.
| ~Fx & ~Hx
2 Universal QuantifierE
4.
| ( Fx & Hx ) v ( ~Fx & ~Hx )
3 vI
5.
| Fx Hx
4 EQUIV
6.
| ( Fx Hx ) G x
1 Universal QuantifierE
7.
| Gx
5,6 E
8.
|Universal Quantifierx Gx
7 Universal QuantifierI
9. Universal Quantifierx( ~Fx & ~Hx )Universal QuantifierxGx 2-8 I

 

5. DERIVE: Cmn

1. Universal Quantifierx( Ax Universal Quantifiery( By Cxy )) PR
2. Am & Bn PR
3. Am Universal Quantifiery( By Cmy ) 1 Universal QuantifierE
4. Am 2 &E
5. Universal Quantifiery( By Cmy ) 3, 4 E
6. Bn Cmn 5 Universal QuantifierE
7. Bn 2 &E
8. Cmn 6, 7 E

 

6. DERIVE:Existential Quantifiery( Cy & Ay )

1. Universal Quantifiery( My Ay ) PR
2. Existential Quantifiery( Cy & My ) PR
3. Ca & Ma 2 Existential QuantifierE
4. Ca 3 &E
5. Ma 3 &E
6. Ma Aa 1 Universal QuantifierE
7. Aa 5, 6 E
8. Ca & Aa 4, 7 &I
9. Existential Quantifiery( Cy & Ay ) 8 Existential QuantifierI

 

7. DERIVE:Universal QuantifierxAx

1. Universal Quantifierx( Ax v Bx ) PR
2. Universal Quantifierx( Bx Ax ) PR
3.
| ~Universal QuantifierxAx
AS
4.
|Existential Quantifierx~Ax
3 QN
5.
| ~Aa
4 Existential QuantifierE
6.
| Aa v Ba
1 Universal QuantifierE
7.
| Ba
5, 6 vE
8.
| Ba Aa
2 Universal QuantifierE
9.
| Aa
7, 8 E
10. Universal QuantifierxAx 3-9 ~E

 

8. DERIVE:Universal QuantifierxUniversal Quantifiery[( Fx Fy ) ( Fy v ~Fx )]

1.
| Fx Fy
AS
2.
| ~Fx v Fy
1 IMP
3.
| Fy v ~Fx
2 COM
4. ( Fx Fy ) ( Fy v ~Fx ) 1-3 I
5.
| Fy v ~Fx
AS
6.
| ~Fx v Fy
5 COM
7.
| Fx Fy
6 IMP
8. ( Fy v ~Fx ) ( Fx Fy ) 5-7 I
9. ( Fx Fy ) ( Fy v ~Fx ) 5, 8 I
10. Universal Quantifiery[( Fx Fy ) ( Fy v ~Fx )] 9 Universal QuantifierI
11. Universal QuantifierxUniversal Quantifiery[( Fx Fy ) ( Fy v ~Fx )] 10 Universal QuantifierI

 

9. DERIVE:Existential Quantifierz ~Jz

1. Universal Quantifiery( Jy ( Ky & Ly )) PR
2. Existential Quantifierx~Kx PR
3. ~Ka 2 Existential QuantifierE
4. ~Ka v ~La 3 vI
5. ~( Ka & La ) 4 DeM
6. Ja ( Ka & La ) 1 Universal QuantifierE
7. ~Ja 5, 6 MT
8. Existential Quantifierz ~Jz 7 Existential QuantifierI

 

10. DERIVE: Universal Quantifierx( Fx Ax )

1. Existential QuantifierxFx Existential Quantifierx( Bx & Cx ) PR
2. Existential Quantifierx( Cx v Dx ) Universal QuantifierxAx PR
3.
| Fx
AS
4.
|Existential QuantifierxFx
3 Existential QuantifierI
5.
|Existential Quantifierx( Bx & Cx )
1, 4 E
6.
| Ba & Ca
5 Existential QuantifierE
7.
| Ca
6 &E
8.
| Ca v Da
7 vI
9.
|Existential Quantifierx( Cx v Dx )
8 Existential QuantifierI
10.
|Universal QuantifierxAx
2, 9 E
11.
| Ax
10 Universal QuantifierE
12. Fx Ax 4-10 I
13. Universal Quantifierx( Fx Ax ) 12 Universal QuantifierI

 

11. DERIVE:Existential Quantifierx ~Fx

1. Universal QuantifierxFx Existential QuantifierxGx PR
2. Universal Quantifierx~Gx PR
3. ~Existential QuantifierxGx 2 QN
4. ~Universal QuantifierxFx 1, 3 MT
5. Existential Quantifierx~Fx 4 QN

 

12. DERIVE: ~Universal QuantifierxAx

1. Universal Quantifierx( Ax & ~Bx ) Existential QuantifierxCx PR
2. ~Existential Quantifierx( Cx v Bx ) PR
3. Universal Quantifierx~( Cx v Bx ) 2 QN
4.
| Universal QuantifierxAx
AS
5.
| Ax
4 Universal QuantifierE
6.
| ~( Cx v Bx )
3 Universal QuantifierE
7.
| ~Cx & ~Bx
6 DeM
8.
| ~Bx
7 &E
9.
| Ax & ~Bx
5, 8 &I
10.
|Universal Quantifierx( Ax & ~Bx )
9 Universal QuantifierI
11.
|Existential QuantifierxCx
1, 10 E
12.
| ~Cx
7 &E
13.
|Universal Quantifierx~Cx
12 Universal QuantifierI
14.
| ~Existential QuantifierxCx
13 QN
15. ~Universal QuantifierxAx 4-14 ~I

 

13. DERIVE:Universal QuantifierxUniversal QuantifieryRxy

1. Existential QuantifierxExistential QuantifieryRxy PR
2. Universal QuantifierxUniversal Quantifiery( Rxy Universal QuantifierzRxz ) PR
3. Universal Quantifierx( Universal QuantifierzRxz Universal QuantifieryRyx ) PR
4. Existential QuantifieryRay 1 Existential QuantifierE
5. Rab 4 Existential QuantifierE
6. Universal Quantifiery( Ray Universal QuantifierzRaz ) 2 Universal QuantifierE
7. Rab Universal QuantifierzRaz 6 Universal QuantifierE
8. Universal QuantifierzRaz 5, 7 E
9. Universal QuantifierzRaz Universal QuantifieryRya 3 Universal QuantifierE
10. Universal QuantifieryRya 8,9 E
11. Rxa 10 Universal QuantifierE
12. "y( Rxy "zRxz ) 2 Universal QuantifierE
13. Rxa Universal QuantifierzRxz 12 Universal QuantifierE
14. Universal QuantifierzRxz 11, 13 E
15. Rxy 14 Universal QuantifierE
16. Universal QuantifieryRxy 15 Universal QuantifierI
17. Universal QuantifierxUniversal QuantifieryRxy 16 Universal QuantifierI

 

14. DERIVE: Universal QuantifierxAx Existential QuantifierxCx

1. Universal QuantifierxAx Existential Quantifierx( Bx & Cx ) PR
2. Universal Quantifierx( Cx Bx ) PR
3.
| Universal QuantifierxAx
AS
4.
|Existential Quantifierx( Bx & Cx )
1, 3 E
5.
| Ba & Ca
4 Existential QuantifierE
6.
| Ca
5 &E
7.
|Existential QuantifierxCx
6 Existential QuantifierI
8. Universal QuantifierxAx Existential QuantifierxCx 3-7 I
9.
| Existential QuantifierxCx
AS
10.
| Cb
9 Existential QuantifierE
11.
| Cb Bb
2 Universal QuantifierE
12.
| Bb
10, 11 E
13.
| Bb & Cb
10, 12 &I
14.
|Existential Quantifierx( Bx & Cx )
13 Existential QuantifierI
15.
|Universal QuantifierxAx
1, 14 E
16. Existential QuantifierxCx Universal QuantifierxAx 9-15 I
17. Universal QuantifierxAx Existential QuantifierxCx 8, 16 I

 

15. DERIVE: ~Universal QuantifierxAx

1. Existential Quantifierx~Ax vExistential Quantifierx~Bx PR
2. Universal QuantifierxBx PR
3. ~~Universal QuantifierxBx 2 DN
4. ~Existential Quantifierx~Bx 3 QN
5. Existential Quantifierx~Ax 1, 4 vE
6. ~Universal QuantifierxAx 5 QN

 

16. DERIVE:Universal Quantifierx( Ax &Existential Quantifiery~Bxy ) ~Existential Quantifierx[ ~Ax vUniversal Quantifiery( Bxy & Bxy )]

1.
| Universal Quantifierx( Ax & Existential Quantifiery~Bxy )
AS
2.
|Universal Quantifierx( ~~Ax &Existential Quantifiery~Bxy )
1 DN
3.
|Universal Quantifierx( ~~Ax & ~Universal QuantifieryBxy )
2 QN
4.
|Universal Quantifierx~( ~Ax vUniversal QuantifieryBxy )
3 DeM
5.
| ~Existential Quantifierx( ~Ax vUniversal QuantifieryBxy )
4 QN
6.
| ~vx[ ~Ax vUniversal Quantifiery(Bxy & Bxy )]
5 IDEM
7. Universal Quantifierx( Ax &Existential Quantifiery~Bxy ) ~Existential Quantifierx[ ~Ax vUniversal Quantifiery( Bxy & Bxy )] 1-5 I
8.
| ~Existential Quantifierx[ ~Ax v Universal Quantifiery(Bxy & Bxy )]
AS
9.
| ~Existential Quantifierx( ~Ax vUniversal QuantifieryBxy )
8 IDEM
10.
|Universal Quantifierx~( ~Ax vUniversal QuantifieryBxy )
9 QN
11.
|Universal Quantifierx( ~~Ax & ~Universal QuantifieryBxy )
10 DeM
12.
|Universal Quantifierx( ~~Ax &Existential Quantifiery~Bxy )
11 QN
13.
|Universal Quantifierx( Ax &Existential Quantifiery~Bxy )
12 DN
14. ~Existential Quantifierx[ ~Ax vUniversal Quantifiery( Bxy & Bxy )] Universal Quantifierx( Ax &Existential Quantifiery~Bxy ) 8-13 I
15. Universal Quantifierx( Ax &Existential Quantifiery~Bxy ) ~Existential Quantifierx[ ~Ax vUniversal Quantifiery( Bxy & Bxy )] 7, 14 I

 

17. DERIVE: ~Universal QuantifierxBx

1. ~Universal Quantifierx( Ax Cx ) PR
2. Universal Quantifierx[( Ax & Bx ) Cx ] PR
3. Existential Quantifierx~( Ax Cx ) 1 QN
4. ~( Aa Ca ) 3 Existential QuantifierE
5. ~( ~Aa v Ca ) 4 IMP
6. ~~Aa & ~Ca 5 DeM
7. ( Aa & Ba ) Ca 2 Universal QuantifierE
8. Aa ( Ba Ca ) 7 EXP
9. ~~Aa 6 &E
10. Aa 9 DN
11. Ba Ca 8, 10 E
12. ~Ca 6 &E
13. ~Ba 11, 12 MT
14. Existential Quantifierx~Bx 13 Existential QuantifierI
15. ~Universal QuantifierxBx 14 QN

 

18. DERIVE:Existential QuantifierxUniversal Quantifiery~Axy

1. Universal QuantifierxExistential QuantifieryAxy Universal QuantifierxExistential QuantifieryBxy PR
2. Existential QuantifierxUniversal Quantifiery~Bxy PR
3. Existential Quantifierx~Existential QuantifieryBxy 2 QN
4. ~Universal QuantifierxExistential QuantifieryBxy 3 QN
5. ~Universal QuantifierxExistential QuantifieryAxy 1, 4 MT
6. Existential Quantifierx~Existential QuantifieryAxy 5 QN
7.  Existential QuantifierxUniversal Quantifiery~Axy 6 QN

 

19. DERIVE:Universal Quantifierx( Bx Existential Quantifiery( Ay & Cyx ))

1. Existential Quantifierx( Ax &Universal Quantifiery( By Cxy )) PR
2. Aa &Universal Quantifiery( By Cay ) 1Existential QuantifierE
3.  Aa 2 &E
4. Universal Quantifiery( By Cay ) 2 &E
5.
| Bx
AS
6.
| Bx Cax
4 Universal QuantifierE
7.
| Cax
5, 6 E
8.
| Aa & Cax
3, 7 &I
9.
|Existential Quantifiery( Ay & Cyx )
8 Existential QuantifierI
10. Bx Existential Quantifiery( Ay & Cyx ) 5-10 I
11. Universal Quantifierx( Bx Existential Quantifiery( Ay & Cyx )) 10 Universal QuantifierI

 

20. DERIVE:Existential QuantifierxCxj

1. Universal Quantifierx[ Ax &Universal Quantifiery( By Cxy )) PR
2. Existential QuantifierxAx Bj PR
3. Aa &Universal Quantifiery( By Cay ) 1 Universal QuantifierE
4. Aa 3 &E
5. Universal Quantifiery( By Cay ) 3 &E
6. Bj Caj 5 Universal QuantifierE
7. Existential QuantifierxAx 4 Existential QuantifierI
8. Bj 2, 7 E
9. Caj 6, 8 E
10. Existential QuantifierxCxj 9 Existential QuantifierI

 

21. DERIVE: Existential Quantifierz( ~Wz & Hz )

1.  Universal Quantifierx(Existential QuantifierxRxy Existential Quantifierz ~Wz ) PR
2. Existential QuantifieryExistential Quantifierz( Ryz & Hz ) PR
3. Universal Quantifierx( ~Hx Wx ) PR
4. Existential Quantifierz( Raz & Hz ) 2 Existential QuantifierE
5. Rab & Hb 4 Existential QuantifierE
6. Rab 5 &E
7. Existential QuantifieryRay 6 Existential QuantifierI
8. Existential QuantifieryRay Existential Quantifierz~Wz 1Universal QuantifierE
9. Existential Quantifierz~Wz 7, 8 E
10. ~Wc 9 Existential QuantifierE
11. ~Hc Wc  3Universal QuantifierE
12. ~~Hc 10, 11 MT
13. Hc 11 DN
14. ~Wc & Hc 10, 13 &I
15. Existential Quantifierz( ~Wz & Hz ) 14 Existential QuantifierI

 

22. DERIVE: [Existential QuantifierxAx (Existential QuantifieryBy Universal QuantifierzCz )] Universal QuantifierxUniversal QuantifieryUniversal Quantifierz[( Ax & By ) Cz ]

1.
|Existential QuantifierxAx ( Existential QuantifieryBy Universal QuantifierzCz )]  
AS
2.
| | Ax & By
AS
3.
| | Ax
2 &E
4.
| |Existential QuantifierxAx
3 Existential QuantifierI
5.
| |Existential QuantifieryBy Universal QuantifierzCz
1, 4 E
6.
| | By
2 &E
7.
| |Existential QuantifieryBy
6 Existential QuantifierI
8.
| |Universal QuantifierzCz
5, 7 E
9.
| | Cz
8 Universal QuantifierE
10.
|( Ax & By ) Cz  
2-9 I
11.
Universal Quantifierz[( Ax & By ) Cz ]  
10 Universal QuantifierI
12.
|Universal QuantifieryUniversal Quantifierz[( Ax & By ) Cz ]  
11 Universal QuantifierI
13.
|Universal QuantifierxUniversal QuantifieryUniversal Quantifierz[( Ax & By ) Cz ]  
12 Universal QuantifierI
14. [Existential QuantifierxAx (Existential QuantifieryBy "zCz )] "x"y"z[( Ax & By ) Cz ] 1-13 I

 

23. DERIVE:Existential Quantifierw( Qw & Bw ) Universal Quantifiery( Lyy ~Ay )

1. Existential QuantifierzQz Universal Quantifierw( Lww ~Hw ) PR 
2. Existential QuantifierxBx Universal Quantifiery( Ay Hy ) PR
3.
| Existential Quantifierw( Qw & Bw )
AS
4.
| Qa & Ba
3 Existential QuantifierE
5.
| Qa
4 &E
6.
|Existential QuantifierzQz
5 Existential QuantifierI
7.
|Universal Quantifierw( Lww ~Hw )
1, 6 E
8.
| Ba
4 &E
9.
|Existential QuantifierxBx
8 Existential QuantifierI
10.
|Universal Quantifiery( Ay Hy )
2, 9 E
11.
| Lyy ~Hy
7 Universal QuantifierE
12.
| Ay Hy
10 Universal QuantifierE
13.
| ~Hy ~Ay
12 TRANS
14.
| Lyy ~Ay
11, 13 HS
15.
|Universal Quantifiery( Lyy ~Ay )
14 Universal QuantifierI
16. Existential Quantifierw( Qw & Bw ) Universal Quantifiery( Lyy ~Ay ) 3-15 I

 

24. DERIVE:Universal QuantifierzUniversal Quantifierw[( Az & Hw ) Czw ]

1. Universal QuantifierxUniversal Quantifiery[( Ax & By ) Cxy ] PR
2. Existential Quantifiery[ Ey &Universal Quantifierw( Hw Cyw )] PR
3. Universal QuantifierxUniversal QuantifieryUniversal Quantifierz[( Cxy & Cyz ) Cxz ] PR
4. Universal Quantifierw( Ew Bw ) PR
5.
| Ax & Hw
AS
6.
| Ax
5 &E
7.
| Hw
5 &E
8.
| Ea &Universal Quantifierw( Hw Caw )
2 Existential QuantifierE
9.
|Universal Quantifierw( Hw Caw )
8 &E
10.
| Hw Caw
9 Universal QuantifierE
11.
| Ea
8 &E
12.
| Ea Ba
4 Universal QuantifierE
13.
| Ba
11, 12 E
14.
|Universal Quantifiery[( Ax & By ) Cxy ]
1 Universal QuantifierE
15.
| ( Ax & Ba ) Cxa
14 "E
16.
| Ax & Ba
6, 13 &I
17.
| Cxa
15, 16 E
18.
| Caw
7, 10 E
19.
| Cxa & Caw
17, 18 &I
20.
|Universal QuantifieryUniversal Quantifierz[( Cxy & Cyz ) Cxz ]
3 Universal QuantifierE
21.
|Universal Quantifierz[( Cxa & Caz ) Cxz ]
20 Universal QuantifierE
22.
| ( Cxy & Cyw ) Cxw
21 Universal QuantifierE
23.
| Cxw
19, 22 E
24. ( Ax & Hw ) Cxw 5-23 I
25. Universal Quantifierw[( Ax & Hw ) Cxw ] 24 Universal QuantifierI
26.. Universal QuantifierzUniversal Quantifierw[( Az & Hw ) Czw ] 25 Universal QuantifierI

 

 

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