Proof of Theorem cgsex4g
| Step | Hyp | Ref
| Expression |
| 1 | | cgsex4g.2 |
. . . . . 6
⊢ (χ
→ (φ ↔ ψ)) |
| 2 | 1 | biimpa 324 |
. . . . 5
⊢ ((χ ∧ φ) → ψ) |
| 3 | 2 | 19.23aivv 953 |
. . . 4
⊢ (∃z∃w(χ ∧ φ) → ψ) |
| 4 | 3 | 19.23aivv 953 |
. . 3
⊢ (∃x∃y∃z∃w(χ ∧ φ) → ψ) |
| 5 | 4 | a1i 7 |
. 2
⊢ (((A
∈ R ∧ B ∈ S)
∧ (C ∈ R ∧ D ∈
S)) → (∃x∃y∃z∃w(χ ∧ φ) → ψ)) |
| 6 | 1 | biimprcd 138 |
. . . . . . 7
⊢ (ψ
→ (χ → φ)) |
| 7 | 6 | ancld 246 |
. . . . . 6
⊢ (ψ
→ (χ → (χ ∧ φ))) |
| 8 | 7 | 19.22dvv 949 |
. . . . 5
⊢ (ψ
→ (∃z∃wχ →
∃z∃w(χ ∧
φ))) |
| 9 | 8 | 19.22dvv 949 |
. . . 4
⊢ (ψ
→ (∃x∃y∃z∃wχ → ∃x∃y∃z∃w(χ ∧ φ))) |
| 10 | | elex 1356 |
. . . . . . . . 9
⊢ (A
∈ R → ∃x x = A) |
| 11 | | elex 1356 |
. . . . . . . . 9
⊢ (B
∈ S → ∃y y = B) |
| 12 | 10, 11 | anim12i 268 |
. . . . . . . 8
⊢ ((A
∈ R ∧ B ∈ S)
→ (∃x x = A ∧
∃y y = B)) |
| 13 | | eeanv 980 |
. . . . . . . 8
⊢ (∃x∃y(x = A ∧ y =
B) ↔ (∃x x = A ∧ ∃y
y = B)) |
| 14 | 12, 13 | sylibr 175 |
. . . . . . 7
⊢ ((A
∈ R ∧ B ∈ S)
→ ∃x∃y(x = A ∧ y =
B)) |
| 15 | | elex 1356 |
. . . . . . . . 9
⊢ (C
∈ R → ∃z z = C) |
| 16 | | elex 1356 |
. . . . . . . . 9
⊢ (D
∈ S → ∃w w = D) |
| 17 | 15, 16 | anim12i 268 |
. . . . . . . 8
⊢ ((C
∈ R ∧ D ∈ S)
→ (∃z z = C ∧
∃w w = D)) |
| 18 | | eeanv 980 |
. . . . . . . 8
⊢ (∃z∃w(z = C ∧ w =
D) ↔ (∃z z = C ∧ ∃w
w = D)) |
| 19 | 17, 18 | sylibr 175 |
. . . . . . 7
⊢ ((C
∈ R ∧ D ∈ S)
→ ∃z∃w(z = C ∧ w =
D)) |
| 20 | 14, 19 | anim12i 268 |
. . . . . 6
⊢ (((A
∈ R ∧ B ∈ S)
∧ (C ∈ R ∧ D ∈
S)) → (∃x∃y(x = A ∧ y =
B) ∧ ∃z∃w(z = C ∧ w =
D))) |
| 21 | | ee4anv 982 |
. . . . . 6
⊢ (∃x∃y∃z∃w((x = A ∧ y =
B) ∧ (z = C ∧
w = D))
↔ (∃x∃y(x = A ∧ y =
B) ∧ ∃z∃w(z = C ∧ w =
D))) |
| 22 | 20, 21 | sylibr 175 |
. . . . 5
⊢ (((A
∈ R ∧ B ∈ S)
∧ (C ∈ R ∧ D ∈
S)) → ∃x∃y∃z∃w((x = A ∧ y =
B) ∧ (z = C ∧
w = D))) |
| 23 | | cgsex4g.1 |
. . . . . . . . 9
⊢ (((x =
A ∧ y = B) ∧
(z = C
∧ w = D)) → χ) |
| 24 | 23 | 19.22i 723 |
. . . . . . . 8
⊢ (∃w((x = A ∧ y =
B) ∧ (z = C ∧
w = D))
→ ∃wχ) |
| 25 | 24 | 19.22i 723 |
. . . . . . 7
⊢ (∃z∃w((x = A ∧ y =
B) ∧ (z = C ∧
w = D))
→ ∃z∃wχ) |
| 26 | 25 | 19.22i 723 |
. . . . . 6
⊢ (∃y∃z∃w((x = A ∧ y =
B) ∧ (z = C ∧
w = D))
→ ∃y∃z∃wχ) |
| 27 | 26 | 19.22i 723 |
. . . . 5
⊢ (∃x∃y∃z∃w((x = A ∧ y =
B) ∧ (z = C ∧
w = D))
→ ∃x∃y∃z∃wχ) |
| 28 | 22, 27 | syl 12 |
. . . 4
⊢ (((A
∈ R ∧ B ∈ S)
∧ (C ∈ R ∧ D ∈
S)) → ∃x∃y∃z∃wχ) |
29| 9, 28 | syl5 22 |
. . 3
⊢ (ψ
→ (((A ∈ R ∧ B ∈
S) ∧ (C ∈ R ∧
D ∈ S)) → ∃x∃y∃z∃w(χ ∧ φ))) | |
| 30 | 29 | com12 13 |
. 2
⊢ (((A
∈ R ∧ B ∈ S)
∧ (C ∈ R ∧ D ∈
S)) → (ψ → ∃x∃y∃z∃w(χ ∧ φ))) |
| 31 | 5, 30 | impbid 397 |
1
⊢ (((A
∈ R ∧ B ∈ S)
∧ (C ∈ R ∧ D ∈
S)) → (∃x∃y∃z∃w(χ ∧ φ) ↔ ψ)) |