Proof of Theorem clwlknf1oclwwlknlem1
| Step | Hyp | Ref | Expression | 
|---|
| 1 |  | clwlkwlk 29795 | . . 3
⊢ (𝐶 ∈ (ClWalks‘𝐺) → 𝐶 ∈ (Walks‘𝐺)) | 
| 2 |  | wlkcpr 29647 | . . . 4
⊢ (𝐶 ∈ (Walks‘𝐺) ↔ (1st
‘𝐶)(Walks‘𝐺)(2nd ‘𝐶)) | 
| 3 |  | eqid 2737 | . . . . . . . 8
⊢
(Vtx‘𝐺) =
(Vtx‘𝐺) | 
| 4 | 3 | wlkpwrd 29635 | . . . . . . 7
⊢
((1st ‘𝐶)(Walks‘𝐺)(2nd ‘𝐶) → (2nd ‘𝐶) ∈ Word (Vtx‘𝐺)) | 
| 5 |  | lencl 14571 | . . . . . . . . 9
⊢
((2nd ‘𝐶) ∈ Word (Vtx‘𝐺) → (♯‘(2nd
‘𝐶)) ∈
ℕ0) | 
| 6 | 4, 5 | syl 17 | . . . . . . . 8
⊢
((1st ‘𝐶)(Walks‘𝐺)(2nd ‘𝐶) → (♯‘(2nd
‘𝐶)) ∈
ℕ0) | 
| 7 |  | wlklenvm1 29640 | . . . . . . . . . . 11
⊢
((1st ‘𝐶)(Walks‘𝐺)(2nd ‘𝐶) → (♯‘(1st
‘𝐶)) =
((♯‘(2nd ‘𝐶)) − 1)) | 
| 8 | 7 | breq2d 5155 | . . . . . . . . . 10
⊢
((1st ‘𝐶)(Walks‘𝐺)(2nd ‘𝐶) → (1 ≤
(♯‘(1st ‘𝐶)) ↔ 1 ≤
((♯‘(2nd ‘𝐶)) − 1))) | 
| 9 |  | 1red 11262 | . . . . . . . . . . . . 13
⊢
((♯‘(2nd ‘𝐶)) ∈ ℕ0 → 1
∈ ℝ) | 
| 10 |  | nn0re 12535 | . . . . . . . . . . . . 13
⊢
((♯‘(2nd ‘𝐶)) ∈ ℕ0 →
(♯‘(2nd ‘𝐶)) ∈ ℝ) | 
| 11 | 9, 9, 10 | leaddsub2d 11865 | . . . . . . . . . . . 12
⊢
((♯‘(2nd ‘𝐶)) ∈ ℕ0 → ((1 +
1) ≤ (♯‘(2nd ‘𝐶)) ↔ 1 ≤
((♯‘(2nd ‘𝐶)) − 1))) | 
| 12 |  | 1p1e2 12391 | . . . . . . . . . . . . . 14
⊢ (1 + 1) =
2 | 
| 13 | 12 | breq1i 5150 | . . . . . . . . . . . . 13
⊢ ((1 + 1)
≤ (♯‘(2nd ‘𝐶)) ↔ 2 ≤
(♯‘(2nd ‘𝐶))) | 
| 14 | 13 | biimpi 216 | . . . . . . . . . . . 12
⊢ ((1 + 1)
≤ (♯‘(2nd ‘𝐶)) → 2 ≤
(♯‘(2nd ‘𝐶))) | 
| 15 | 11, 14 | biimtrrdi 254 | . . . . . . . . . . 11
⊢
((♯‘(2nd ‘𝐶)) ∈ ℕ0 → (1 ≤
((♯‘(2nd ‘𝐶)) − 1) → 2 ≤
(♯‘(2nd ‘𝐶)))) | 
| 16 | 4, 5, 15 | 3syl 18 | . . . . . . . . . 10
⊢
((1st ‘𝐶)(Walks‘𝐺)(2nd ‘𝐶) → (1 ≤
((♯‘(2nd ‘𝐶)) − 1) → 2 ≤
(♯‘(2nd ‘𝐶)))) | 
| 17 | 8, 16 | sylbid 240 | . . . . . . . . 9
⊢
((1st ‘𝐶)(Walks‘𝐺)(2nd ‘𝐶) → (1 ≤
(♯‘(1st ‘𝐶)) → 2 ≤
(♯‘(2nd ‘𝐶)))) | 
| 18 | 17 | imp 406 | . . . . . . . 8
⊢
(((1st ‘𝐶)(Walks‘𝐺)(2nd ‘𝐶) ∧ 1 ≤
(♯‘(1st ‘𝐶))) → 2 ≤
(♯‘(2nd ‘𝐶))) | 
| 19 |  | ige2m1fz 13657 | . . . . . . . 8
⊢
(((♯‘(2nd ‘𝐶)) ∈ ℕ0 ∧ 2 ≤
(♯‘(2nd ‘𝐶))) → ((♯‘(2nd
‘𝐶)) − 1)
∈ (0...(♯‘(2nd ‘𝐶)))) | 
| 20 | 6, 18, 19 | syl2an2r 685 | . . . . . . 7
⊢
(((1st ‘𝐶)(Walks‘𝐺)(2nd ‘𝐶) ∧ 1 ≤
(♯‘(1st ‘𝐶))) → ((♯‘(2nd
‘𝐶)) − 1)
∈ (0...(♯‘(2nd ‘𝐶)))) | 
| 21 |  | pfxlen 14721 | . . . . . . 7
⊢
(((2nd ‘𝐶) ∈ Word (Vtx‘𝐺) ∧ ((♯‘(2nd
‘𝐶)) − 1)
∈ (0...(♯‘(2nd ‘𝐶)))) → (♯‘((2nd
‘𝐶) prefix
((♯‘(2nd ‘𝐶)) − 1))) =
((♯‘(2nd ‘𝐶)) − 1)) | 
| 22 | 4, 20, 21 | syl2an2r 685 | . . . . . 6
⊢
(((1st ‘𝐶)(Walks‘𝐺)(2nd ‘𝐶) ∧ 1 ≤
(♯‘(1st ‘𝐶))) → (♯‘((2nd
‘𝐶) prefix
((♯‘(2nd ‘𝐶)) − 1))) =
((♯‘(2nd ‘𝐶)) − 1)) | 
| 23 | 7 | eqcomd 2743 | . . . . . . 7
⊢
((1st ‘𝐶)(Walks‘𝐺)(2nd ‘𝐶) → ((♯‘(2nd
‘𝐶)) − 1) =
(♯‘(1st ‘𝐶))) | 
| 24 | 23 | adantr 480 | . . . . . 6
⊢
(((1st ‘𝐶)(Walks‘𝐺)(2nd ‘𝐶) ∧ 1 ≤
(♯‘(1st ‘𝐶))) → ((♯‘(2nd
‘𝐶)) − 1) =
(♯‘(1st ‘𝐶))) | 
| 25 | 22, 24 | eqtrd 2777 | . . . . 5
⊢
(((1st ‘𝐶)(Walks‘𝐺)(2nd ‘𝐶) ∧ 1 ≤
(♯‘(1st ‘𝐶))) → (♯‘((2nd
‘𝐶) prefix
((♯‘(2nd ‘𝐶)) − 1))) =
(♯‘(1st ‘𝐶))) | 
| 26 | 25 | ex 412 | . . . 4
⊢
((1st ‘𝐶)(Walks‘𝐺)(2nd ‘𝐶) → (1 ≤
(♯‘(1st ‘𝐶)) → (♯‘((2nd
‘𝐶) prefix
((♯‘(2nd ‘𝐶)) − 1))) =
(♯‘(1st ‘𝐶)))) | 
| 27 | 2, 26 | sylbi 217 | . . 3
⊢ (𝐶 ∈ (Walks‘𝐺) → (1 ≤
(♯‘(1st ‘𝐶)) → (♯‘((2nd
‘𝐶) prefix
((♯‘(2nd ‘𝐶)) − 1))) =
(♯‘(1st ‘𝐶)))) | 
| 28 | 1, 27 | syl 17 | . 2
⊢ (𝐶 ∈ (ClWalks‘𝐺) → (1 ≤
(♯‘(1st ‘𝐶)) → (♯‘((2nd
‘𝐶) prefix
((♯‘(2nd ‘𝐶)) − 1))) =
(♯‘(1st ‘𝐶)))) | 
| 29 | 28 | imp 406 | 1
⊢ ((𝐶 ∈ (ClWalks‘𝐺) ∧ 1 ≤
(♯‘(1st ‘𝐶))) → (♯‘((2nd
‘𝐶) prefix
((♯‘(2nd ‘𝐶)) − 1))) =
(♯‘(1st ‘𝐶))) |