Proof of Theorem cvnbtwnt
| Step | Hyp | Ref
| Expression |
| 1 | | cvbrt 5714 |
. . . . 5
⊢ ((A
∈ Cℋ ∧ B
∈ Cℋ ) → (A ⋖ B
↔ (A ⊂ B ∧ ¬ ∃x ∈ Cℋ (A ⊂ x ∧
x ⊂ B)))) |
| 2 | | psseq2 1560 |
. . . . . . . . . . 11
⊢ (x =
C → (A ⊂ x ↔
A ⊂ C)) |
| 3 | | psseq1 1559 |
. . . . . . . . . . 11
⊢ (x =
C → (x ⊂ B ↔
C ⊂ B)) |
| 4 | 2, 3 | anbi12d 476 |
. . . . . . . . . 10
⊢ (x =
C → ((A ⊂ x ∧
x ⊂ B) ↔ (A
⊂ C ∧ C ⊂ B))) |
| 5 | 4 | rcla4ev 1403 |
. . . . . . . . 9
⊢ ((C
∈ Cℋ ∧ (A
⊂ C ∧ C ⊂ B))
→ ∃x ∈
Cℋ (A ⊂
x ∧ x ⊂ B)) |
| 6 | 5 | exp 291 |
. . . . . . . 8
⊢ (C
∈ Cℋ → ((A ⊂ C ∧
C ⊂ B) → ∃x ∈ Cℋ (A ⊂ x ∧
x ⊂ B))) |
| 7 | 6 | con3d 87 |
. . . . . . 7
⊢ (C
∈ Cℋ → (¬ ∃x ∈ Cℋ (A ⊂ x ∧
x ⊂ B) → ¬ (A ⊂ C ∧
C ⊂ B))) |
| 8 | 7 | com12 13 |
. . . . . 6
⊢ (¬ ∃x ∈ Cℋ (A ⊂ x ∧
x ⊂ B) → (C
∈ Cℋ → ¬ (A ⊂ C ∧
C ⊂ B))) |
| 9 | 8 | adantl 305 |
. . . . 5
⊢ ((A
⊂ B ∧ ¬ ∃x ∈ Cℋ (A ⊂ x ∧
x ⊂ B)) → (C
∈ Cℋ → ¬ (A ⊂ C ∧
C ⊂ B))) |
| 10 | 1, 9 | syl6bi 187 |
. . . 4
⊢ ((A
∈ Cℋ ∧ B
∈ Cℋ ) → (A ⋖ B
→ (C ∈ Cℋ
→ ¬ (A ⊂ C ∧ C ⊂
B)))) |
| 11 | 10 | com23 32 |
. . 3
⊢ ((A
∈ Cℋ ∧ B
∈ Cℋ ) → (C ∈ Cℋ → (A ⋖ B
→ ¬ (A ⊂ C ∧ C ⊂
B)))) |
| 12 | 11 | imp 277 |
. 2
⊢ (((A
∈ Cℋ ∧ B
∈ Cℋ ) ∧ C
∈ Cℋ ) → (A ⋖ B
→ ¬ (A ⊂ C ∧ C ⊂
B))) |
| 13 | 12 | 3impa 609 |
1
⊢ ((A
∈ Cℋ ∧ B
∈ Cℋ ∧ C
∈ Cℋ ) → (A ⋖ B
→ ¬ (A ⊂ C ∧ C ⊂
B))) |