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Theorem numclwwlkovf2ex 27219

Description: Extending a closed walk starting at a fixed vertex by an additional edge (forth and back). (Contributed by AV, 22-Sep-2018.) (Proof shortened by AV, 25-Jan-2022.)

**Hypotheses**
Ref	Expression
numclwwlkovf.f	⊢ 𝐹 = (𝑣 ∈ 𝑉, 𝑛 ∈ ℕ ↦ {𝑤 ∈ (𝑛 ClWWalksN 𝐺) ∣ (𝑤‘0) = 𝑣})
numclwwlkffin.v	⊢ 𝑉 = (Vtx‘𝐺)
numclwwlkovfel2.e	⊢ 𝐸 = (Edg‘𝐺)

**Assertion**
Ref	Expression
numclwwlkovf2ex	⊢ (((𝐺 ∈ USGraph ∧ 𝑋 ∈ 𝑉 ∧ 𝑁 ∈ (ℤ_≥‘3)) ∧ 𝑌 ∈ (𝐺 NeighbVtx 𝑋) ∧ 𝑊 ∈ (𝑋𝐹(𝑁 − 2))) → ((𝑊 ++ ⟨“𝑋”⟩) ++ ⟨“𝑌”⟩) ∈ (𝑁 ClWWalksN 𝐺))

Distinct variable groups: 𝑛,𝐺,𝑣,𝑤 𝑛,𝑁,𝑣,𝑤 𝑛,𝑉,𝑣 𝑛,𝑋,𝑣,𝑤 𝑤,𝑊 𝑤,𝑉 Allowed substitution hints: 𝐸(𝑤,𝑣,𝑛) 𝐹(𝑤,𝑣,𝑛) 𝑊(𝑣,𝑛) 𝑌(𝑤,𝑣,𝑛)

Proof of Theorem numclwwlkovf2ex Dummy variable 𝑖 is distinct from all other variables.

Step	Hyp	Ref	Expression
1		simp1 1061	. . . . . 6 ⊢ ((𝐺 ∈ USGraph ∧ 𝑋 ∈ 𝑉 ∧ 𝑁 ∈ (ℤ_≥‘3)) → 𝐺 ∈ USGraph )
2		uz3m2nn 11731	. . . . . . 7 ⊢ (𝑁 ∈ (ℤ_≥‘3) → (𝑁 − 2) ∈ ℕ)
3	2	3ad2ant3 1084	. . . . . 6 ⊢ ((𝐺 ∈ USGraph ∧ 𝑋 ∈ 𝑉 ∧ 𝑁 ∈ (ℤ_≥‘3)) → (𝑁 − 2) ∈ ℕ)
4		simp2 1062	. . . . . 6 ⊢ ((𝐺 ∈ USGraph ∧ 𝑋 ∈ 𝑉 ∧ 𝑁 ∈ (ℤ_≥‘3)) → 𝑋 ∈ 𝑉)
5		numclwwlkovf.f	. . . . . . 7 ⊢ 𝐹 = (𝑣 ∈ 𝑉, 𝑛 ∈ ℕ ↦ {𝑤 ∈ (𝑛 ClWWalksN 𝐺) ∣ (𝑤‘0) = 𝑣})
6		numclwwlkffin.v	. . . . . . 7 ⊢ 𝑉 = (Vtx‘𝐺)
7		numclwwlkovfel2.e	. . . . . . 7 ⊢ 𝐸 = (Edg‘𝐺)
8	5, 6, 7	numclwwlkovfel2 27216	. . . . . 6 ⊢ ((𝐺 ∈ USGraph ∧ (𝑁 − 2) ∈ ℕ ∧ 𝑋 ∈ 𝑉) → (𝑊 ∈ (𝑋𝐹(𝑁 − 2)) ↔ ((𝑊 ∈ Word 𝑉 ∧ ∀𝑖 ∈ (0..^((#‘𝑊) − 1)){(𝑊‘𝑖), (𝑊‘(𝑖 + 1))} ∈ 𝐸 ∧ {( lastS ‘𝑊), (𝑊‘0)} ∈ 𝐸) ∧ (#‘𝑊) = (𝑁 − 2) ∧ (𝑊‘0) = 𝑋)))
9	1, 3, 4, 8	syl3anc 1326	. . . . 5 ⊢ ((𝐺 ∈ USGraph ∧ 𝑋 ∈ 𝑉 ∧ 𝑁 ∈ (ℤ_≥‘3)) → (𝑊 ∈ (𝑋𝐹(𝑁 − 2)) ↔ ((𝑊 ∈ Word 𝑉 ∧ ∀𝑖 ∈ (0..^((#‘𝑊) − 1)){(𝑊‘𝑖), (𝑊‘(𝑖 + 1))} ∈ 𝐸 ∧ {( lastS ‘𝑊), (𝑊‘0)} ∈ 𝐸) ∧ (#‘𝑊) = (𝑁 − 2) ∧ (𝑊‘0) = 𝑋)))
10		simpr11 1145	. . . . . . . . . 10 ⊢ (((𝐺 ∈ USGraph ∧ 𝑋 ∈ 𝑉 ∧ 𝑁 ∈ (ℤ_≥‘3)) ∧ ((𝑊 ∈ Word 𝑉 ∧ ∀𝑖 ∈ (0..^((#‘𝑊) − 1)){(𝑊‘𝑖), (𝑊‘(𝑖 + 1))} ∈ 𝐸 ∧ {( lastS ‘𝑊), (𝑊‘0)} ∈ 𝐸) ∧ (#‘𝑊) = (𝑁 − 2) ∧ (𝑊‘0) = 𝑋)) → 𝑊 ∈ Word 𝑉)
11	10	adantr 481	. . . . . . . . 9 ⊢ ((((𝐺 ∈ USGraph ∧ 𝑋 ∈ 𝑉 ∧ 𝑁 ∈ (ℤ_≥‘3)) ∧ ((𝑊 ∈ Word 𝑉 ∧ ∀𝑖 ∈ (0..^((#‘𝑊) − 1)){(𝑊‘𝑖), (𝑊‘(𝑖 + 1))} ∈ 𝐸 ∧ {( lastS ‘𝑊), (𝑊‘0)} ∈ 𝐸) ∧ (#‘𝑊) = (𝑁 − 2) ∧ (𝑊‘0) = 𝑋)) ∧ 𝑌 ∈ (𝐺 NeighbVtx 𝑋)) → 𝑊 ∈ Word 𝑉)
12		simpll2 1101	. . . . . . . . 9 ⊢ ((((𝐺 ∈ USGraph ∧ 𝑋 ∈ 𝑉 ∧ 𝑁 ∈ (ℤ_≥‘3)) ∧ ((𝑊 ∈ Word 𝑉 ∧ ∀𝑖 ∈ (0..^((#‘𝑊) − 1)){(𝑊‘𝑖), (𝑊‘(𝑖 + 1))} ∈ 𝐸 ∧ {( lastS ‘𝑊), (𝑊‘0)} ∈ 𝐸) ∧ (#‘𝑊) = (𝑁 − 2) ∧ (𝑊‘0) = 𝑋)) ∧ 𝑌 ∈ (𝐺 NeighbVtx 𝑋)) → 𝑋 ∈ 𝑉)
13	6	nbgrisvtx 26255	. . . . . . . . . . . . 13 ⊢ ((𝐺 ∈ USGraph ∧ 𝑌 ∈ (𝐺 NeighbVtx 𝑋)) → 𝑌 ∈ 𝑉)
14	13	ex 450	. . . . . . . . . . . 12 ⊢ (𝐺 ∈ USGraph → (𝑌 ∈ (𝐺 NeighbVtx 𝑋) → 𝑌 ∈ 𝑉))
15	14	3ad2ant1 1082	. . . . . . . . . . 11 ⊢ ((𝐺 ∈ USGraph ∧ 𝑋 ∈ 𝑉 ∧ 𝑁 ∈ (ℤ_≥‘3)) → (𝑌 ∈ (𝐺 NeighbVtx 𝑋) → 𝑌 ∈ 𝑉))
16	15	adantr 481	. . . . . . . . . 10 ⊢ (((𝐺 ∈ USGraph ∧ 𝑋 ∈ 𝑉 ∧ 𝑁 ∈ (ℤ_≥‘3)) ∧ ((𝑊 ∈ Word 𝑉 ∧ ∀𝑖 ∈ (0..^((#‘𝑊) − 1)){(𝑊‘𝑖), (𝑊‘(𝑖 + 1))} ∈ 𝐸 ∧ {( lastS ‘𝑊), (𝑊‘0)} ∈ 𝐸) ∧ (#‘𝑊) = (𝑁 − 2) ∧ (𝑊‘0) = 𝑋)) → (𝑌 ∈ (𝐺 NeighbVtx 𝑋) → 𝑌 ∈ 𝑉))
17	16	imp 445	. . . . . . . . 9 ⊢ ((((𝐺 ∈ USGraph ∧ 𝑋 ∈ 𝑉 ∧ 𝑁 ∈ (ℤ_≥‘3)) ∧ ((𝑊 ∈ Word 𝑉 ∧ ∀𝑖 ∈ (0..^((#‘𝑊) − 1)){(𝑊‘𝑖), (𝑊‘(𝑖 + 1))} ∈ 𝐸 ∧ {( lastS ‘𝑊), (𝑊‘0)} ∈ 𝐸) ∧ (#‘𝑊) = (𝑁 − 2) ∧ (𝑊‘0) = 𝑋)) ∧ 𝑌 ∈ (𝐺 NeighbVtx 𝑋)) → 𝑌 ∈ 𝑉)
18		ccatw2s1cl 13401	. . . . . . . . 9 ⊢ ((𝑊 ∈ Word 𝑉 ∧ 𝑋 ∈ 𝑉 ∧ 𝑌 ∈ 𝑉) → ((𝑊 ++ ⟨“𝑋”⟩) ++ ⟨“𝑌”⟩) ∈ Word 𝑉)
19	11, 12, 17, 18	syl3anc 1326	. . . . . . . 8 ⊢ ((((𝐺 ∈ USGraph ∧ 𝑋 ∈ 𝑉 ∧ 𝑁 ∈ (ℤ_≥‘3)) ∧ ((𝑊 ∈ Word 𝑉 ∧ ∀𝑖 ∈ (0..^((#‘𝑊) − 1)){(𝑊‘𝑖), (𝑊‘(𝑖 + 1))} ∈ 𝐸 ∧ {( lastS ‘𝑊), (𝑊‘0)} ∈ 𝐸) ∧ (#‘𝑊) = (𝑁 − 2) ∧ (𝑊‘0) = 𝑋)) ∧ 𝑌 ∈ (𝐺 NeighbVtx 𝑋)) → ((𝑊 ++ ⟨“𝑋”⟩) ++ ⟨“𝑌”⟩) ∈ Word 𝑉)
20	6, 7	numclwwlkovf2exlem2 27212	. . . . . . . . 9 ⊢ ((((𝐺 ∈ USGraph ∧ 𝑋 ∈ 𝑉 ∧ 𝑁 ∈ (ℤ_≥‘3)) ∧ ((𝑊 ∈ Word 𝑉 ∧ ∀𝑖 ∈ (0..^((#‘𝑊) − 1)){(𝑊‘𝑖), (𝑊‘(𝑖 + 1))} ∈ 𝐸 ∧ {( lastS ‘𝑊), (𝑊‘0)} ∈ 𝐸) ∧ (#‘𝑊) = (𝑁 − 2) ∧ (𝑊‘0) = 𝑋)) ∧ 𝑌 ∈ (𝐺 NeighbVtx 𝑋)) → ∀𝑖 ∈ ((0..^((#‘𝑊) − 1)) ∪ {((#‘𝑊) − 1), (#‘𝑊)}){(((𝑊 ++ ⟨“𝑋”⟩) ++ ⟨“𝑌”⟩)‘𝑖), (((𝑊 ++ ⟨“𝑋”⟩) ++ ⟨“𝑌”⟩)‘(𝑖 + 1))} ∈ 𝐸)
21		simp11 1091	. . . . . . . . . . . . . . 15 ⊢ (((𝑊 ∈ Word 𝑉 ∧ ∀𝑖 ∈ (0..^((#‘𝑊) − 1)){(𝑊‘𝑖), (𝑊‘(𝑖 + 1))} ∈ 𝐸 ∧ {( lastS ‘𝑊), (𝑊‘0)} ∈ 𝐸) ∧ (#‘𝑊) = (𝑁 − 2) ∧ (𝑊‘0) = 𝑋) → 𝑊 ∈ Word 𝑉)
22	21	ad2antlr 763	. . . . . . . . . . . . . 14 ⊢ ((((𝐺 ∈ USGraph ∧ 𝑋 ∈ 𝑉 ∧ 𝑁 ∈ (ℤ_≥‘3)) ∧ ((𝑊 ∈ Word 𝑉 ∧ ∀𝑖 ∈ (0..^((#‘𝑊) − 1)){(𝑊‘𝑖), (𝑊‘(𝑖 + 1))} ∈ 𝐸 ∧ {( lastS ‘𝑊), (𝑊‘0)} ∈ 𝐸) ∧ (#‘𝑊) = (𝑁 − 2) ∧ (𝑊‘0) = 𝑋)) ∧ 𝑌 ∈ (𝐺 NeighbVtx 𝑋)) → 𝑊 ∈ Word 𝑉)
23		ccatw2s1len 13402	. . . . . . . . . . . . . 14 ⊢ ((𝑊 ∈ Word 𝑉 ∧ 𝑋 ∈ 𝑉 ∧ 𝑌 ∈ 𝑉) → (#‘((𝑊 ++ ⟨“𝑋”⟩) ++ ⟨“𝑌”⟩)) = ((#‘𝑊) + 2))
24	22, 12, 17, 23	syl3anc 1326	. . . . . . . . . . . . 13 ⊢ ((((𝐺 ∈ USGraph ∧ 𝑋 ∈ 𝑉 ∧ 𝑁 ∈ (ℤ_≥‘3)) ∧ ((𝑊 ∈ Word 𝑉 ∧ ∀𝑖 ∈ (0..^((#‘𝑊) − 1)){(𝑊‘𝑖), (𝑊‘(𝑖 + 1))} ∈ 𝐸 ∧ {( lastS ‘𝑊), (𝑊‘0)} ∈ 𝐸) ∧ (#‘𝑊) = (𝑁 − 2) ∧ (𝑊‘0) = 𝑋)) ∧ 𝑌 ∈ (𝐺 NeighbVtx 𝑋)) → (#‘((𝑊 ++ ⟨“𝑋”⟩) ++ ⟨“𝑌”⟩)) = ((#‘𝑊) + 2))
25	24	oveq1d 6665	. . . . . . . . . . . 12 ⊢ ((((𝐺 ∈ USGraph ∧ 𝑋 ∈ 𝑉 ∧ 𝑁 ∈ (ℤ_≥‘3)) ∧ ((𝑊 ∈ Word 𝑉 ∧ ∀𝑖 ∈ (0..^((#‘𝑊) − 1)){(𝑊‘𝑖), (𝑊‘(𝑖 + 1))} ∈ 𝐸 ∧ {( lastS ‘𝑊), (𝑊‘0)} ∈ 𝐸) ∧ (#‘𝑊) = (𝑁 − 2) ∧ (𝑊‘0) = 𝑋)) ∧ 𝑌 ∈ (𝐺 NeighbVtx 𝑋)) → ((#‘((𝑊 ++ ⟨“𝑋”⟩) ++ ⟨“𝑌”⟩)) − 1) = (((#‘𝑊) + 2) − 1))
26	25	oveq2d 6666	. . . . . . . . . . 11 ⊢ ((((𝐺 ∈ USGraph ∧ 𝑋 ∈ 𝑉 ∧ 𝑁 ∈ (ℤ_≥‘3)) ∧ ((𝑊 ∈ Word 𝑉 ∧ ∀𝑖 ∈ (0..^((#‘𝑊) − 1)){(𝑊‘𝑖), (𝑊‘(𝑖 + 1))} ∈ 𝐸 ∧ {( lastS ‘𝑊), (𝑊‘0)} ∈ 𝐸) ∧ (#‘𝑊) = (𝑁 − 2) ∧ (𝑊‘0) = 𝑋)) ∧ 𝑌 ∈ (𝐺 NeighbVtx 𝑋)) → (0..^((#‘((𝑊 ++ ⟨“𝑋”⟩) ++ ⟨“𝑌”⟩)) − 1)) = (0..^(((#‘𝑊) + 2) − 1)))
27		simp3 1063	. . . . . . . . . . . . . 14 ⊢ ((𝐺 ∈ USGraph ∧ 𝑋 ∈ 𝑉 ∧ 𝑁 ∈ (ℤ_≥‘3)) → 𝑁 ∈ (ℤ_≥‘3))
28		simp2 1062	. . . . . . . . . . . . . 14 ⊢ (((𝑊 ∈ Word 𝑉 ∧ ∀𝑖 ∈ (0..^((#‘𝑊) − 1)){(𝑊‘𝑖), (𝑊‘(𝑖 + 1))} ∈ 𝐸 ∧ {( lastS ‘𝑊), (𝑊‘0)} ∈ 𝐸) ∧ (#‘𝑊) = (𝑁 − 2) ∧ (𝑊‘0) = 𝑋) → (#‘𝑊) = (𝑁 − 2))
29	27, 28	anim12i 590	. . . . . . . . . . . . 13 ⊢ (((𝐺 ∈ USGraph ∧ 𝑋 ∈ 𝑉 ∧ 𝑁 ∈ (ℤ_≥‘3)) ∧ ((𝑊 ∈ Word 𝑉 ∧ ∀𝑖 ∈ (0..^((#‘𝑊) − 1)){(𝑊‘𝑖), (𝑊‘(𝑖 + 1))} ∈ 𝐸 ∧ {( lastS ‘𝑊), (𝑊‘0)} ∈ 𝐸) ∧ (#‘𝑊) = (𝑁 − 2) ∧ (𝑊‘0) = 𝑋)) → (𝑁 ∈ (ℤ_≥‘3) ∧ (#‘𝑊) = (𝑁 − 2)))
30	29	adantr 481	. . . . . . . . . . . 12 ⊢ ((((𝐺 ∈ USGraph ∧ 𝑋 ∈ 𝑉 ∧ 𝑁 ∈ (ℤ_≥‘3)) ∧ ((𝑊 ∈ Word 𝑉 ∧ ∀𝑖 ∈ (0..^((#‘𝑊) − 1)){(𝑊‘𝑖), (𝑊‘(𝑖 + 1))} ∈ 𝐸 ∧ {( lastS ‘𝑊), (𝑊‘0)} ∈ 𝐸) ∧ (#‘𝑊) = (𝑁 − 2) ∧ (𝑊‘0) = 𝑋)) ∧ 𝑌 ∈ (𝐺 NeighbVtx 𝑋)) → (𝑁 ∈ (ℤ_≥‘3) ∧ (#‘𝑊) = (𝑁 − 2)))
31		numclwwlkovf2exlem1 27211	. . . . . . . . . . . 12 ⊢ ((𝑁 ∈ (ℤ_≥‘3) ∧ (#‘𝑊) = (𝑁 − 2)) → (0..^(((#‘𝑊) + 2) − 1)) = ((0..^((#‘𝑊) − 1)) ∪ {((#‘𝑊) − 1), (#‘𝑊)}))
32	30, 31	syl 17	. . . . . . . . . . 11 ⊢ ((((𝐺 ∈ USGraph ∧ 𝑋 ∈ 𝑉 ∧ 𝑁 ∈ (ℤ_≥‘3)) ∧ ((𝑊 ∈ Word 𝑉 ∧ ∀𝑖 ∈ (0..^((#‘𝑊) − 1)){(𝑊‘𝑖), (𝑊‘(𝑖 + 1))} ∈ 𝐸 ∧ {( lastS ‘𝑊), (𝑊‘0)} ∈ 𝐸) ∧ (#‘𝑊) = (𝑁 − 2) ∧ (𝑊‘0) = 𝑋)) ∧ 𝑌 ∈ (𝐺 NeighbVtx 𝑋)) → (0..^(((#‘𝑊) + 2) − 1)) = ((0..^((#‘𝑊) − 1)) ∪ {((#‘𝑊) − 1), (#‘𝑊)}))
33	26, 32	eqtrd 2656	. . . . . . . . . 10 ⊢ ((((𝐺 ∈ USGraph ∧ 𝑋 ∈ 𝑉 ∧ 𝑁 ∈ (ℤ_≥‘3)) ∧ ((𝑊 ∈ Word 𝑉 ∧ ∀𝑖 ∈ (0..^((#‘𝑊) − 1)){(𝑊‘𝑖), (𝑊‘(𝑖 + 1))} ∈ 𝐸 ∧ {( lastS ‘𝑊), (𝑊‘0)} ∈ 𝐸) ∧ (#‘𝑊) = (𝑁 − 2) ∧ (𝑊‘0) = 𝑋)) ∧ 𝑌 ∈ (𝐺 NeighbVtx 𝑋)) → (0..^((#‘((𝑊 ++ ⟨“𝑋”⟩) ++ ⟨“𝑌”⟩)) − 1)) = ((0..^((#‘𝑊) − 1)) ∪ {((#‘𝑊) − 1), (#‘𝑊)}))
34	33	raleqdv 3144	. . . . . . . . 9 ⊢ ((((𝐺 ∈ USGraph ∧ 𝑋 ∈ 𝑉 ∧ 𝑁 ∈ (ℤ_≥‘3)) ∧ ((𝑊 ∈ Word 𝑉 ∧ ∀𝑖 ∈ (0..^((#‘𝑊) − 1)){(𝑊‘𝑖), (𝑊‘(𝑖 + 1))} ∈ 𝐸 ∧ {( lastS ‘𝑊), (𝑊‘0)} ∈ 𝐸) ∧ (#‘𝑊) = (𝑁 − 2) ∧ (𝑊‘0) = 𝑋)) ∧ 𝑌 ∈ (𝐺 NeighbVtx 𝑋)) → (∀𝑖 ∈ (0..^((#‘((𝑊 ++ ⟨“𝑋”⟩) ++ ⟨“𝑌”⟩)) − 1)){(((𝑊 ++ ⟨“𝑋”⟩) ++ ⟨“𝑌”⟩)‘𝑖), (((𝑊 ++ ⟨“𝑋”⟩) ++ ⟨“𝑌”⟩)‘(𝑖 + 1))} ∈ 𝐸 ↔ ∀𝑖 ∈ ((0..^((#‘𝑊) − 1)) ∪ {((#‘𝑊) − 1), (#‘𝑊)}){(((𝑊 ++ ⟨“𝑋”⟩) ++ ⟨“𝑌”⟩)‘𝑖), (((𝑊 ++ ⟨“𝑋”⟩) ++ ⟨“𝑌”⟩)‘(𝑖 + 1))} ∈ 𝐸))
35	20, 34	mpbird 247	. . . . . . . 8 ⊢ ((((𝐺 ∈ USGraph ∧ 𝑋 ∈ 𝑉 ∧ 𝑁 ∈ (ℤ_≥‘3)) ∧ ((𝑊 ∈ Word 𝑉 ∧ ∀𝑖 ∈ (0..^((#‘𝑊) − 1)){(𝑊‘𝑖), (𝑊‘(𝑖 + 1))} ∈ 𝐸 ∧ {( lastS ‘𝑊), (𝑊‘0)} ∈ 𝐸) ∧ (#‘𝑊) = (𝑁 − 2) ∧ (𝑊‘0) = 𝑋)) ∧ 𝑌 ∈ (𝐺 NeighbVtx 𝑋)) → ∀𝑖 ∈ (0..^((#‘((𝑊 ++ ⟨“𝑋”⟩) ++ ⟨“𝑌”⟩)) − 1)){(((𝑊 ++ ⟨“𝑋”⟩) ++ ⟨“𝑌”⟩)‘𝑖), (((𝑊 ++ ⟨“𝑋”⟩) ++ ⟨“𝑌”⟩)‘(𝑖 + 1))} ∈ 𝐸)
36		ccatws1cl 13396	. . . . . . . . . . . 12 ⊢ ((𝑊 ∈ Word 𝑉 ∧ 𝑋 ∈ 𝑉) → (𝑊 ++ ⟨“𝑋”⟩) ∈ Word 𝑉)
37		lswccats1 13411	. . . . . . . . . . . 12 ⊢ (((𝑊 ++ ⟨“𝑋”⟩) ∈ Word 𝑉 ∧ 𝑌 ∈ 𝑉) → ( lastS ‘((𝑊 ++ ⟨“𝑋”⟩) ++ ⟨“𝑌”⟩)) = 𝑌)
38	36, 37	stoic3 1701	. . . . . . . . . . 11 ⊢ ((𝑊 ∈ Word 𝑉 ∧ 𝑋 ∈ 𝑉 ∧ 𝑌 ∈ 𝑉) → ( lastS ‘((𝑊 ++ ⟨“𝑋”⟩) ++ ⟨“𝑌”⟩)) = 𝑌)
39	22, 12, 17, 38	syl3anc 1326	. . . . . . . . . 10 ⊢ ((((𝐺 ∈ USGraph ∧ 𝑋 ∈ 𝑉 ∧ 𝑁 ∈ (ℤ_≥‘3)) ∧ ((𝑊 ∈ Word 𝑉 ∧ ∀𝑖 ∈ (0..^((#‘𝑊) − 1)){(𝑊‘𝑖), (𝑊‘(𝑖 + 1))} ∈ 𝐸 ∧ {( lastS ‘𝑊), (𝑊‘0)} ∈ 𝐸) ∧ (#‘𝑊) = (𝑁 − 2) ∧ (𝑊‘0) = 𝑋)) ∧ 𝑌 ∈ (𝐺 NeighbVtx 𝑋)) → ( lastS ‘((𝑊 ++ ⟨“𝑋”⟩) ++ ⟨“𝑌”⟩)) = 𝑌)
40	2	nngt0d 11064	. . . . . . . . . . . . . . . . 17 ⊢ (𝑁 ∈ (ℤ_≥‘3) → 0 < (𝑁 − 2))
41		breq2 4657	. . . . . . . . . . . . . . . . 17 ⊢ ((#‘𝑊) = (𝑁 − 2) → (0 < (#‘𝑊) ↔ 0 < (𝑁 − 2)))
42	40, 41	syl5ibr 236	. . . . . . . . . . . . . . . 16 ⊢ ((#‘𝑊) = (𝑁 − 2) → (𝑁 ∈ (ℤ_≥‘3) → 0 < (#‘𝑊)))
43	42	3ad2ant2 1083	. . . . . . . . . . . . . . 15 ⊢ (((𝑊 ∈ Word 𝑉 ∧ ∀𝑖 ∈ (0..^((#‘𝑊) − 1)){(𝑊‘𝑖), (𝑊‘(𝑖 + 1))} ∈ 𝐸 ∧ {( lastS ‘𝑊), (𝑊‘0)} ∈ 𝐸) ∧ (#‘𝑊) = (𝑁 − 2) ∧ (𝑊‘0) = 𝑋) → (𝑁 ∈ (ℤ_≥‘3) → 0 < (#‘𝑊)))
44	43	com12 32	. . . . . . . . . . . . . 14 ⊢ (𝑁 ∈ (ℤ_≥‘3) → (((𝑊 ∈ Word 𝑉 ∧ ∀𝑖 ∈ (0..^((#‘𝑊) − 1)){(𝑊‘𝑖), (𝑊‘(𝑖 + 1))} ∈ 𝐸 ∧ {( lastS ‘𝑊), (𝑊‘0)} ∈ 𝐸) ∧ (#‘𝑊) = (𝑁 − 2) ∧ (𝑊‘0) = 𝑋) → 0 < (#‘𝑊)))
45	44	3ad2ant3 1084	. . . . . . . . . . . . 13 ⊢ ((𝐺 ∈ USGraph ∧ 𝑋 ∈ 𝑉 ∧ 𝑁 ∈ (ℤ_≥‘3)) → (((𝑊 ∈ Word 𝑉 ∧ ∀𝑖 ∈ (0..^((#‘𝑊) − 1)){(𝑊‘𝑖), (𝑊‘(𝑖 + 1))} ∈ 𝐸 ∧ {( lastS ‘𝑊), (𝑊‘0)} ∈ 𝐸) ∧ (#‘𝑊) = (𝑁 − 2) ∧ (𝑊‘0) = 𝑋) → 0 < (#‘𝑊)))
46	45	imp 445	. . . . . . . . . . . 12 ⊢ (((𝐺 ∈ USGraph ∧ 𝑋 ∈ 𝑉 ∧ 𝑁 ∈ (ℤ_≥‘3)) ∧ ((𝑊 ∈ Word 𝑉 ∧ ∀𝑖 ∈ (0..^((#‘𝑊) − 1)){(𝑊‘𝑖), (𝑊‘(𝑖 + 1))} ∈ 𝐸 ∧ {( lastS ‘𝑊), (𝑊‘0)} ∈ 𝐸) ∧ (#‘𝑊) = (𝑁 − 2) ∧ (𝑊‘0) = 𝑋)) → 0 < (#‘𝑊))
47	46	adantr 481	. . . . . . . . . . 11 ⊢ ((((𝐺 ∈ USGraph ∧ 𝑋 ∈ 𝑉 ∧ 𝑁 ∈ (ℤ_≥‘3)) ∧ ((𝑊 ∈ Word 𝑉 ∧ ∀𝑖 ∈ (0..^((#‘𝑊) − 1)){(𝑊‘𝑖), (𝑊‘(𝑖 + 1))} ∈ 𝐸 ∧ {( lastS ‘𝑊), (𝑊‘0)} ∈ 𝐸) ∧ (#‘𝑊) = (𝑁 − 2) ∧ (𝑊‘0) = 𝑋)) ∧ 𝑌 ∈ (𝐺 NeighbVtx 𝑋)) → 0 < (#‘𝑊))
48		ccat2s1fst 13416	. . . . . . . . . . 11 ⊢ (((𝑊 ∈ Word 𝑉 ∧ 0 < (#‘𝑊)) ∧ (𝑋 ∈ 𝑉 ∧ 𝑌 ∈ 𝑉)) → (((𝑊 ++ ⟨“𝑋”⟩) ++ ⟨“𝑌”⟩)‘0) = (𝑊‘0))
49	22, 47, 12, 17, 48	syl22anc 1327	. . . . . . . . . 10 ⊢ ((((𝐺 ∈ USGraph ∧ 𝑋 ∈ 𝑉 ∧ 𝑁 ∈ (ℤ_≥‘3)) ∧ ((𝑊 ∈ Word 𝑉 ∧ ∀𝑖 ∈ (0..^((#‘𝑊) − 1)){(𝑊‘𝑖), (𝑊‘(𝑖 + 1))} ∈ 𝐸 ∧ {( lastS ‘𝑊), (𝑊‘0)} ∈ 𝐸) ∧ (#‘𝑊) = (𝑁 − 2) ∧ (𝑊‘0) = 𝑋)) ∧ 𝑌 ∈ (𝐺 NeighbVtx 𝑋)) → (((𝑊 ++ ⟨“𝑋”⟩) ++ ⟨“𝑌”⟩)‘0) = (𝑊‘0))
50	39, 49	preq12d 4276	. . . . . . . . 9 ⊢ ((((𝐺 ∈ USGraph ∧ 𝑋 ∈ 𝑉 ∧ 𝑁 ∈ (ℤ_≥‘3)) ∧ ((𝑊 ∈ Word 𝑉 ∧ ∀𝑖 ∈ (0..^((#‘𝑊) − 1)){(𝑊‘𝑖), (𝑊‘(𝑖 + 1))} ∈ 𝐸 ∧ {( lastS ‘𝑊), (𝑊‘0)} ∈ 𝐸) ∧ (#‘𝑊) = (𝑁 − 2) ∧ (𝑊‘0) = 𝑋)) ∧ 𝑌 ∈ (𝐺 NeighbVtx 𝑋)) → {( lastS ‘((𝑊 ++ ⟨“𝑋”⟩) ++ ⟨“𝑌”⟩)), (((𝑊 ++ ⟨“𝑋”⟩) ++ ⟨“𝑌”⟩)‘0)} = {𝑌, (𝑊‘0)})
51	7	nbusgreledg 26249	. . . . . . . . . . . . 13 ⊢ (𝐺 ∈ USGraph → (𝑌 ∈ (𝐺 NeighbVtx 𝑋) ↔ {𝑌, 𝑋} ∈ 𝐸))
52	51	3ad2ant1 1082	. . . . . . . . . . . 12 ⊢ ((𝐺 ∈ USGraph ∧ 𝑋 ∈ 𝑉 ∧ 𝑁 ∈ (ℤ_≥‘3)) → (𝑌 ∈ (𝐺 NeighbVtx 𝑋) ↔ {𝑌, 𝑋} ∈ 𝐸))
53	52	adantr 481	. . . . . . . . . . 11 ⊢ (((𝐺 ∈ USGraph ∧ 𝑋 ∈ 𝑉 ∧ 𝑁 ∈ (ℤ_≥‘3)) ∧ ((𝑊 ∈ Word 𝑉 ∧ ∀𝑖 ∈ (0..^((#‘𝑊) − 1)){(𝑊‘𝑖), (𝑊‘(𝑖 + 1))} ∈ 𝐸 ∧ {( lastS ‘𝑊), (𝑊‘0)} ∈ 𝐸) ∧ (#‘𝑊) = (𝑁 − 2) ∧ (𝑊‘0) = 𝑋)) → (𝑌 ∈ (𝐺 NeighbVtx 𝑋) ↔ {𝑌, 𝑋} ∈ 𝐸))
54	53	biimpa 501	. . . . . . . . . 10 ⊢ ((((𝐺 ∈ USGraph ∧ 𝑋 ∈ 𝑉 ∧ 𝑁 ∈ (ℤ_≥‘3)) ∧ ((𝑊 ∈ Word 𝑉 ∧ ∀𝑖 ∈ (0..^((#‘𝑊) − 1)){(𝑊‘𝑖), (𝑊‘(𝑖 + 1))} ∈ 𝐸 ∧ {( lastS ‘𝑊), (𝑊‘0)} ∈ 𝐸) ∧ (#‘𝑊) = (𝑁 − 2) ∧ (𝑊‘0) = 𝑋)) ∧ 𝑌 ∈ (𝐺 NeighbVtx 𝑋)) → {𝑌, 𝑋} ∈ 𝐸)
55		preq2 4269	. . . . . . . . . . . . 13 ⊢ ((𝑊‘0) = 𝑋 → {𝑌, (𝑊‘0)} = {𝑌, 𝑋})
56	55	eleq1d 2686	. . . . . . . . . . . 12 ⊢ ((𝑊‘0) = 𝑋 → ({𝑌, (𝑊‘0)} ∈ 𝐸 ↔ {𝑌, 𝑋} ∈ 𝐸))
57	56	3ad2ant3 1084	. . . . . . . . . . 11 ⊢ (((𝑊 ∈ Word 𝑉 ∧ ∀𝑖 ∈ (0..^((#‘𝑊) − 1)){(𝑊‘𝑖), (𝑊‘(𝑖 + 1))} ∈ 𝐸 ∧ {( lastS ‘𝑊), (𝑊‘0)} ∈ 𝐸) ∧ (#‘𝑊) = (𝑁 − 2) ∧ (𝑊‘0) = 𝑋) → ({𝑌, (𝑊‘0)} ∈ 𝐸 ↔ {𝑌, 𝑋} ∈ 𝐸))
58	57	ad2antlr 763	. . . . . . . . . 10 ⊢ ((((𝐺 ∈ USGraph ∧ 𝑋 ∈ 𝑉 ∧ 𝑁 ∈ (ℤ_≥‘3)) ∧ ((𝑊 ∈ Word 𝑉 ∧ ∀𝑖 ∈ (0..^((#‘𝑊) − 1)){(𝑊‘𝑖), (𝑊‘(𝑖 + 1))} ∈ 𝐸 ∧ {( lastS ‘𝑊), (𝑊‘0)} ∈ 𝐸) ∧ (#‘𝑊) = (𝑁 − 2) ∧ (𝑊‘0) = 𝑋)) ∧ 𝑌 ∈ (𝐺 NeighbVtx 𝑋)) → ({𝑌, (𝑊‘0)} ∈ 𝐸 ↔ {𝑌, 𝑋} ∈ 𝐸))
59	54, 58	mpbird 247	. . . . . . . . 9 ⊢ ((((𝐺 ∈ USGraph ∧ 𝑋 ∈ 𝑉 ∧ 𝑁 ∈ (ℤ_≥‘3)) ∧ ((𝑊 ∈ Word 𝑉 ∧ ∀𝑖 ∈ (0..^((#‘𝑊) − 1)){(𝑊‘𝑖), (𝑊‘(𝑖 + 1))} ∈ 𝐸 ∧ {( lastS ‘𝑊), (𝑊‘0)} ∈ 𝐸) ∧ (#‘𝑊) = (𝑁 − 2) ∧ (𝑊‘0) = 𝑋)) ∧ 𝑌 ∈ (𝐺 NeighbVtx 𝑋)) → {𝑌, (𝑊‘0)} ∈ 𝐸)
60	50, 59	eqeltrd 2701	. . . . . . . 8 ⊢ ((((𝐺 ∈ USGraph ∧ 𝑋 ∈ 𝑉 ∧ 𝑁 ∈ (ℤ_≥‘3)) ∧ ((𝑊 ∈ Word 𝑉 ∧ ∀𝑖 ∈ (0..^((#‘𝑊) − 1)){(𝑊‘𝑖), (𝑊‘(𝑖 + 1))} ∈ 𝐸 ∧ {( lastS ‘𝑊), (𝑊‘0)} ∈ 𝐸) ∧ (#‘𝑊) = (𝑁 − 2) ∧ (𝑊‘0) = 𝑋)) ∧ 𝑌 ∈ (𝐺 NeighbVtx 𝑋)) → {( lastS ‘((𝑊 ++ ⟨“𝑋”⟩) ++ ⟨“𝑌”⟩)), (((𝑊 ++ ⟨“𝑋”⟩) ++ ⟨“𝑌”⟩)‘0)} ∈ 𝐸)
61	19, 35, 60	3jca 1242	. . . . . . 7 ⊢ ((((𝐺 ∈ USGraph ∧ 𝑋 ∈ 𝑉 ∧ 𝑁 ∈ (ℤ_≥‘3)) ∧ ((𝑊 ∈ Word 𝑉 ∧ ∀𝑖 ∈ (0..^((#‘𝑊) − 1)){(𝑊‘𝑖), (𝑊‘(𝑖 + 1))} ∈ 𝐸 ∧ {( lastS ‘𝑊), (𝑊‘0)} ∈ 𝐸) ∧ (#‘𝑊) = (𝑁 − 2) ∧ (𝑊‘0) = 𝑋)) ∧ 𝑌 ∈ (𝐺 NeighbVtx 𝑋)) → (((𝑊 ++ ⟨“𝑋”⟩) ++ ⟨“𝑌”⟩) ∈ Word 𝑉 ∧ ∀𝑖 ∈ (0..^((#‘((𝑊 ++ ⟨“𝑋”⟩) ++ ⟨“𝑌”⟩)) − 1)){(((𝑊 ++ ⟨“𝑋”⟩) ++ ⟨“𝑌”⟩)‘𝑖), (((𝑊 ++ ⟨“𝑋”⟩) ++ ⟨“𝑌”⟩)‘(𝑖 + 1))} ∈ 𝐸 ∧ {( lastS ‘((𝑊 ++ ⟨“𝑋”⟩) ++ ⟨“𝑌”⟩)), (((𝑊 ++ ⟨“𝑋”⟩) ++ ⟨“𝑌”⟩)‘0)} ∈ 𝐸))
62		oveq1 6657	. . . . . . . . . . . . . . 15 ⊢ ((#‘𝑊) = (𝑁 − 2) → ((#‘𝑊) + 2) = ((𝑁 − 2) + 2))
63		eluzelcn 11699	. . . . . . . . . . . . . . . 16 ⊢ (𝑁 ∈ (ℤ_≥‘3) → 𝑁 ∈ ℂ)
64		2cn 11091	. . . . . . . . . . . . . . . 16 ⊢ 2 ∈ ℂ
65		npcan 10290	. . . . . . . . . . . . . . . 16 ⊢ ((𝑁 ∈ ℂ ∧ 2 ∈ ℂ) → ((𝑁 − 2) + 2) = 𝑁)
66	63, 64, 65	sylancl 694	. . . . . . . . . . . . . . 15 ⊢ (𝑁 ∈ (ℤ_≥‘3) → ((𝑁 − 2) + 2) = 𝑁)
67	62, 66	sylan9eq 2676	. . . . . . . . . . . . . 14 ⊢ (((#‘𝑊) = (𝑁 − 2) ∧ 𝑁 ∈ (ℤ_≥‘3)) → ((#‘𝑊) + 2) = 𝑁)
68	67	ex 450	. . . . . . . . . . . . 13 ⊢ ((#‘𝑊) = (𝑁 − 2) → (𝑁 ∈ (ℤ_≥‘3) → ((#‘𝑊) + 2) = 𝑁))
69	68	3ad2ant2 1083	. . . . . . . . . . . 12 ⊢ (((𝑊 ∈ Word 𝑉 ∧ ∀𝑖 ∈ (0..^((#‘𝑊) − 1)){(𝑊‘𝑖), (𝑊‘(𝑖 + 1))} ∈ 𝐸 ∧ {( lastS ‘𝑊), (𝑊‘0)} ∈ 𝐸) ∧ (#‘𝑊) = (𝑁 − 2) ∧ (𝑊‘0) = 𝑋) → (𝑁 ∈ (ℤ_≥‘3) → ((#‘𝑊) + 2) = 𝑁))
70	69	com12 32	. . . . . . . . . . 11 ⊢ (𝑁 ∈ (ℤ_≥‘3) → (((𝑊 ∈ Word 𝑉 ∧ ∀𝑖 ∈ (0..^((#‘𝑊) − 1)){(𝑊‘𝑖), (𝑊‘(𝑖 + 1))} ∈ 𝐸 ∧ {( lastS ‘𝑊), (𝑊‘0)} ∈ 𝐸) ∧ (#‘𝑊) = (𝑁 − 2) ∧ (𝑊‘0) = 𝑋) → ((#‘𝑊) + 2) = 𝑁))
71	70	3ad2ant3 1084	. . . . . . . . . 10 ⊢ ((𝐺 ∈ USGraph ∧ 𝑋 ∈ 𝑉 ∧ 𝑁 ∈ (ℤ_≥‘3)) → (((𝑊 ∈ Word 𝑉 ∧ ∀𝑖 ∈ (0..^((#‘𝑊) − 1)){(𝑊‘𝑖), (𝑊‘(𝑖 + 1))} ∈ 𝐸 ∧ {( lastS ‘𝑊), (𝑊‘0)} ∈ 𝐸) ∧ (#‘𝑊) = (𝑁 − 2) ∧ (𝑊‘0) = 𝑋) → ((#‘𝑊) + 2) = 𝑁))
72	71	imp 445	. . . . . . . . 9 ⊢ (((𝐺 ∈ USGraph ∧ 𝑋 ∈ 𝑉 ∧ 𝑁 ∈ (ℤ_≥‘3)) ∧ ((𝑊 ∈ Word 𝑉 ∧ ∀𝑖 ∈ (0..^((#‘𝑊) − 1)){(𝑊‘𝑖), (𝑊‘(𝑖 + 1))} ∈ 𝐸 ∧ {( lastS ‘𝑊), (𝑊‘0)} ∈ 𝐸) ∧ (#‘𝑊) = (𝑁 − 2) ∧ (𝑊‘0) = 𝑋)) → ((#‘𝑊) + 2) = 𝑁)
73	72	adantr 481	. . . . . . . 8 ⊢ ((((𝐺 ∈ USGraph ∧ 𝑋 ∈ 𝑉 ∧ 𝑁 ∈ (ℤ_≥‘3)) ∧ ((𝑊 ∈ Word 𝑉 ∧ ∀𝑖 ∈ (0..^((#‘𝑊) − 1)){(𝑊‘𝑖), (𝑊‘(𝑖 + 1))} ∈ 𝐸 ∧ {( lastS ‘𝑊), (𝑊‘0)} ∈ 𝐸) ∧ (#‘𝑊) = (𝑁 − 2) ∧ (𝑊‘0) = 𝑋)) ∧ 𝑌 ∈ (𝐺 NeighbVtx 𝑋)) → ((#‘𝑊) + 2) = 𝑁)
74	24, 73	eqtrd 2656	. . . . . . 7 ⊢ ((((𝐺 ∈ USGraph ∧ 𝑋 ∈ 𝑉 ∧ 𝑁 ∈ (ℤ_≥‘3)) ∧ ((𝑊 ∈ Word 𝑉 ∧ ∀𝑖 ∈ (0..^((#‘𝑊) − 1)){(𝑊‘𝑖), (𝑊‘(𝑖 + 1))} ∈ 𝐸 ∧ {( lastS ‘𝑊), (𝑊‘0)} ∈ 𝐸) ∧ (#‘𝑊) = (𝑁 − 2) ∧ (𝑊‘0) = 𝑋)) ∧ 𝑌 ∈ (𝐺 NeighbVtx 𝑋)) → (#‘((𝑊 ++ ⟨“𝑋”⟩) ++ ⟨“𝑌”⟩)) = 𝑁)
75	61, 74	jca 554	. . . . . 6 ⊢ ((((𝐺 ∈ USGraph ∧ 𝑋 ∈ 𝑉 ∧ 𝑁 ∈ (ℤ_≥‘3)) ∧ ((𝑊 ∈ Word 𝑉 ∧ ∀𝑖 ∈ (0..^((#‘𝑊) − 1)){(𝑊‘𝑖), (𝑊‘(𝑖 + 1))} ∈ 𝐸 ∧ {( lastS ‘𝑊), (𝑊‘0)} ∈ 𝐸) ∧ (#‘𝑊) = (𝑁 − 2) ∧ (𝑊‘0) = 𝑋)) ∧ 𝑌 ∈ (𝐺 NeighbVtx 𝑋)) → ((((𝑊 ++ ⟨“𝑋”⟩) ++ ⟨“𝑌”⟩) ∈ Word 𝑉 ∧ ∀𝑖 ∈ (0..^((#‘((𝑊 ++ ⟨“𝑋”⟩) ++ ⟨“𝑌”⟩)) − 1)){(((𝑊 ++ ⟨“𝑋”⟩) ++ ⟨“𝑌”⟩)‘𝑖), (((𝑊 ++ ⟨“𝑋”⟩) ++ ⟨“𝑌”⟩)‘(𝑖 + 1))} ∈ 𝐸 ∧ {( lastS ‘((𝑊 ++ ⟨“𝑋”⟩) ++ ⟨“𝑌”⟩)), (((𝑊 ++ ⟨“𝑋”⟩) ++ ⟨“𝑌”⟩)‘0)} ∈ 𝐸) ∧ (#‘((𝑊 ++ ⟨“𝑋”⟩) ++ ⟨“𝑌”⟩)) = 𝑁))
76	75	exp31 630	. . . . 5 ⊢ ((𝐺 ∈ USGraph ∧ 𝑋 ∈ 𝑉 ∧ 𝑁 ∈ (ℤ_≥‘3)) → (((𝑊 ∈ Word 𝑉 ∧ ∀𝑖 ∈ (0..^((#‘𝑊) − 1)){(𝑊‘𝑖), (𝑊‘(𝑖 + 1))} ∈ 𝐸 ∧ {( lastS ‘𝑊), (𝑊‘0)} ∈ 𝐸) ∧ (#‘𝑊) = (𝑁 − 2) ∧ (𝑊‘0) = 𝑋) → (𝑌 ∈ (𝐺 NeighbVtx 𝑋) → ((((𝑊 ++ ⟨“𝑋”⟩) ++ ⟨“𝑌”⟩) ∈ Word 𝑉 ∧ ∀𝑖 ∈ (0..^((#‘((𝑊 ++ ⟨“𝑋”⟩) ++ ⟨“𝑌”⟩)) − 1)){(((𝑊 ++ ⟨“𝑋”⟩) ++ ⟨“𝑌”⟩)‘𝑖), (((𝑊 ++ ⟨“𝑋”⟩) ++ ⟨“𝑌”⟩)‘(𝑖 + 1))} ∈ 𝐸 ∧ {( lastS ‘((𝑊 ++ ⟨“𝑋”⟩) ++ ⟨“𝑌”⟩)), (((𝑊 ++ ⟨“𝑋”⟩) ++ ⟨“𝑌”⟩)‘0)} ∈ 𝐸) ∧ (#‘((𝑊 ++ ⟨“𝑋”⟩) ++ ⟨“𝑌”⟩)) = 𝑁))))
77	9, 76	sylbid 230	. . . 4 ⊢ ((𝐺 ∈ USGraph ∧ 𝑋 ∈ 𝑉 ∧ 𝑁 ∈ (ℤ_≥‘3)) → (𝑊 ∈ (𝑋𝐹(𝑁 − 2)) → (𝑌 ∈ (𝐺 NeighbVtx 𝑋) → ((((𝑊 ++ ⟨“𝑋”⟩) ++ ⟨“𝑌”⟩) ∈ Word 𝑉 ∧ ∀𝑖 ∈ (0..^((#‘((𝑊 ++ ⟨“𝑋”⟩) ++ ⟨“𝑌”⟩)) − 1)){(((𝑊 ++ ⟨“𝑋”⟩) ++ ⟨“𝑌”⟩)‘𝑖), (((𝑊 ++ ⟨“𝑋”⟩) ++ ⟨“𝑌”⟩)‘(𝑖 + 1))} ∈ 𝐸 ∧ {( lastS ‘((𝑊 ++ ⟨“𝑋”⟩) ++ ⟨“𝑌”⟩)), (((𝑊 ++ ⟨“𝑋”⟩) ++ ⟨“𝑌”⟩)‘0)} ∈ 𝐸) ∧ (#‘((𝑊 ++ ⟨“𝑋”⟩) ++ ⟨“𝑌”⟩)) = 𝑁))))
78	77	com23 86	. . 3 ⊢ ((𝐺 ∈ USGraph ∧ 𝑋 ∈ 𝑉 ∧ 𝑁 ∈ (ℤ_≥‘3)) → (𝑌 ∈ (𝐺 NeighbVtx 𝑋) → (𝑊 ∈ (𝑋𝐹(𝑁 − 2)) → ((((𝑊 ++ ⟨“𝑋”⟩) ++ ⟨“𝑌”⟩) ∈ Word 𝑉 ∧ ∀𝑖 ∈ (0..^((#‘((𝑊 ++ ⟨“𝑋”⟩) ++ ⟨“𝑌”⟩)) − 1)){(((𝑊 ++ ⟨“𝑋”⟩) ++ ⟨“𝑌”⟩)‘𝑖), (((𝑊 ++ ⟨“𝑋”⟩) ++ ⟨“𝑌”⟩)‘(𝑖 + 1))} ∈ 𝐸 ∧ {( lastS ‘((𝑊 ++ ⟨“𝑋”⟩) ++ ⟨“𝑌”⟩)), (((𝑊 ++ ⟨“𝑋”⟩) ++ ⟨“𝑌”⟩)‘0)} ∈ 𝐸) ∧ (#‘((𝑊 ++ ⟨“𝑋”⟩) ++ ⟨“𝑌”⟩)) = 𝑁))))
79	78	3imp 1256	. 2 ⊢ (((𝐺 ∈ USGraph ∧ 𝑋 ∈ 𝑉 ∧ 𝑁 ∈ (ℤ_≥‘3)) ∧ 𝑌 ∈ (𝐺 NeighbVtx 𝑋) ∧ 𝑊 ∈ (𝑋𝐹(𝑁 − 2))) → ((((𝑊 ++ ⟨“𝑋”⟩) ++ ⟨“𝑌”⟩) ∈ Word 𝑉 ∧ ∀𝑖 ∈ (0..^((#‘((𝑊 ++ ⟨“𝑋”⟩) ++ ⟨“𝑌”⟩)) − 1)){(((𝑊 ++ ⟨“𝑋”⟩) ++ ⟨“𝑌”⟩)‘𝑖), (((𝑊 ++ ⟨“𝑋”⟩) ++ ⟨“𝑌”⟩)‘(𝑖 + 1))} ∈ 𝐸 ∧ {( lastS ‘((𝑊 ++ ⟨“𝑋”⟩) ++ ⟨“𝑌”⟩)), (((𝑊 ++ ⟨“𝑋”⟩) ++ ⟨“𝑌”⟩)‘0)} ∈ 𝐸) ∧ (#‘((𝑊 ++ ⟨“𝑋”⟩) ++ ⟨“𝑌”⟩)) = 𝑁))
80		eluzge3nn 11730	. . . . 5 ⊢ (𝑁 ∈ (ℤ_≥‘3) → 𝑁 ∈ ℕ)
81	6, 7	isclwwlksnx 26889	. . . . 5 ⊢ (𝑁 ∈ ℕ → (((𝑊 ++ ⟨“𝑋”⟩) ++ ⟨“𝑌”⟩) ∈ (𝑁 ClWWalksN 𝐺) ↔ ((((𝑊 ++ ⟨“𝑋”⟩) ++ ⟨“𝑌”⟩) ∈ Word 𝑉 ∧ ∀𝑖 ∈ (0..^((#‘((𝑊 ++ ⟨“𝑋”⟩) ++ ⟨“𝑌”⟩)) − 1)){(((𝑊 ++ ⟨“𝑋”⟩) ++ ⟨“𝑌”⟩)‘𝑖), (((𝑊 ++ ⟨“𝑋”⟩) ++ ⟨“𝑌”⟩)‘(𝑖 + 1))} ∈ 𝐸 ∧ {( lastS ‘((𝑊 ++ ⟨“𝑋”⟩) ++ ⟨“𝑌”⟩)), (((𝑊 ++ ⟨“𝑋”⟩) ++ ⟨“𝑌”⟩)‘0)} ∈ 𝐸) ∧ (#‘((𝑊 ++ ⟨“𝑋”⟩) ++ ⟨“𝑌”⟩)) = 𝑁)))
82	80, 81	syl 17	. . . 4 ⊢ (𝑁 ∈ (ℤ_≥‘3) → (((𝑊 ++ ⟨“𝑋”⟩) ++ ⟨“𝑌”⟩) ∈ (𝑁 ClWWalksN 𝐺) ↔ ((((𝑊 ++ ⟨“𝑋”⟩) ++ ⟨“𝑌”⟩) ∈ Word 𝑉 ∧ ∀𝑖 ∈ (0..^((#‘((𝑊 ++ ⟨“𝑋”⟩) ++ ⟨“𝑌”⟩)) − 1)){(((𝑊 ++ ⟨“𝑋”⟩) ++ ⟨“𝑌”⟩)‘𝑖), (((𝑊 ++ ⟨“𝑋”⟩) ++ ⟨“𝑌”⟩)‘(𝑖 + 1))} ∈ 𝐸 ∧ {( lastS ‘((𝑊 ++ ⟨“𝑋”⟩) ++ ⟨“𝑌”⟩)), (((𝑊 ++ ⟨“𝑋”⟩) ++ ⟨“𝑌”⟩)‘0)} ∈ 𝐸) ∧ (#‘((𝑊 ++ ⟨“𝑋”⟩) ++ ⟨“𝑌”⟩)) = 𝑁)))
83	82	3ad2ant3 1084	. . 3 ⊢ ((𝐺 ∈ USGraph ∧ 𝑋 ∈ 𝑉 ∧ 𝑁 ∈ (ℤ_≥‘3)) → (((𝑊 ++ ⟨“𝑋”⟩) ++ ⟨“𝑌”⟩) ∈ (𝑁 ClWWalksN 𝐺) ↔ ((((𝑊 ++ ⟨“𝑋”⟩) ++ ⟨“𝑌”⟩) ∈ Word 𝑉 ∧ ∀𝑖 ∈ (0..^((#‘((𝑊 ++ ⟨“𝑋”⟩) ++ ⟨“𝑌”⟩)) − 1)){(((𝑊 ++ ⟨“𝑋”⟩) ++ ⟨“𝑌”⟩)‘𝑖), (((𝑊 ++ ⟨“𝑋”⟩) ++ ⟨“𝑌”⟩)‘(𝑖 + 1))} ∈ 𝐸 ∧ {( lastS ‘((𝑊 ++ ⟨“𝑋”⟩) ++ ⟨“𝑌”⟩)), (((𝑊 ++ ⟨“𝑋”⟩) ++ ⟨“𝑌”⟩)‘0)} ∈ 𝐸) ∧ (#‘((𝑊 ++ ⟨“𝑋”⟩) ++ ⟨“𝑌”⟩)) = 𝑁)))
84	83	3ad2ant1 1082	. 2 ⊢ (((𝐺 ∈ USGraph ∧ 𝑋 ∈ 𝑉 ∧ 𝑁 ∈ (ℤ_≥‘3)) ∧ 𝑌 ∈ (𝐺 NeighbVtx 𝑋) ∧ 𝑊 ∈ (𝑋𝐹(𝑁 − 2))) → (((𝑊 ++ ⟨“𝑋”⟩) ++ ⟨“𝑌”⟩) ∈ (𝑁 ClWWalksN 𝐺) ↔ ((((𝑊 ++ ⟨“𝑋”⟩) ++ ⟨“𝑌”⟩) ∈ Word 𝑉 ∧ ∀𝑖 ∈ (0..^((#‘((𝑊 ++ ⟨“𝑋”⟩) ++ ⟨“𝑌”⟩)) − 1)){(((𝑊 ++ ⟨“𝑋”⟩) ++ ⟨“𝑌”⟩)‘𝑖), (((𝑊 ++ ⟨“𝑋”⟩) ++ ⟨“𝑌”⟩)‘(𝑖 + 1))} ∈ 𝐸 ∧ {( lastS ‘((𝑊 ++ ⟨“𝑋”⟩) ++ ⟨“𝑌”⟩)), (((𝑊 ++ ⟨“𝑋”⟩) ++ ⟨“𝑌”⟩)‘0)} ∈ 𝐸) ∧ (#‘((𝑊 ++ ⟨“𝑋”⟩) ++ ⟨“𝑌”⟩)) = 𝑁)))
85	79, 84	mpbird 247	1 ⊢ (((𝐺 ∈ USGraph ∧ 𝑋 ∈ 𝑉 ∧ 𝑁 ∈ (ℤ_≥‘3)) ∧ 𝑌 ∈ (𝐺 NeighbVtx 𝑋) ∧ 𝑊 ∈ (𝑋𝐹(𝑁 − 2))) → ((𝑊 ++ ⟨“𝑋”⟩) ++ ⟨“𝑌”⟩) ∈ (𝑁 ClWWalksN 𝐺))

Colors of variables: wff setvar class

Syntax hints: → wi 4 ↔ wb 196 ∧ wa 384 ∧ w3a 1037 = wceq 1483 ∈ wcel 1990 ∀wral 2912 {crab 2916 ∪ cun 3572 {cpr 4179 class class class wbr 4653 ‘cfv 5888 (class class class)co 6650 ↦ cmpt2 6652 ℂcc 9934 0cc0 9936 1c1 9937 + caddc 9939 < clt 10074 − cmin 10266 ℕcn 11020 2c2 11070 3c3 11071 ℤ_≥cuz 11687 ..^cfzo 12465 #chash 13117 Word cword 13291 lastS clsw 13292 ++ cconcat 13293 ⟨“cs1 13294 Vtxcvtx 25874 Edgcedg 25939 USGraph cusgr 26044 NeighbVtx cnbgr 26224 ClWWalksN cclwwlksn 26876

This theorem was proved from axioms: ax-mp 5 ax-1 6 ax-2 7 ax-3 8 ax-gen 1722 ax-4 1737 ax-5 1839 ax-6 1888 ax-7 1935 ax-8 1992 ax-9 1999 ax-10 2019 ax-11 2034 ax-12 2047 ax-13 2246 ax-ext 2602 ax-rep 4771 ax-sep 4781 ax-nul 4789 ax-pow 4843 ax-pr 4906 ax-un 6949 ax-cnex 9992 ax-resscn 9993 ax-1cn 9994 ax-icn 9995 ax-addcl 9996 ax-addrcl 9997 ax-mulcl 9998 ax-mulrcl 9999 ax-mulcom 10000 ax-addass 10001 ax-mulass 10002 ax-distr 10003 ax-i2m1 10004 ax-1ne0 10005 ax-1rid 10006 ax-rnegex 10007 ax-rrecex 10008 ax-cnre 10009 ax-pre-lttri 10010 ax-pre-lttrn 10011 ax-pre-ltadd 10012 ax-pre-mulgt0 10013

This theorem depends on definitions: df-bi 197 df-or 385 df-an 386 df-3or 1038 df-3an 1039 df-tru 1486 df-fal 1489 df-ex 1705 df-nf 1710 df-sb 1881 df-eu 2474 df-mo 2475 df-clab 2609 df-cleq 2615 df-clel 2618 df-nfc 2753 df-ne 2795 df-nel 2898 df-ral 2917 df-rex 2918 df-reu 2919 df-rmo 2920 df-rab 2921 df-v 3202 df-sbc 3436 df-csb 3534 df-dif 3577 df-un 3579 df-in 3581 df-ss 3588 df-pss 3590 df-nul 3916 df-if 4087 df-pw 4160 df-sn 4178 df-pr 4180 df-tp 4182 df-op 4184 df-uni 4437 df-int 4476 df-iun 4522 df-br 4654 df-opab 4713 df-mpt 4730 df-tr 4753 df-id 5024 df-eprel 5029 df-po 5035 df-so 5036 df-fr 5073 df-we 5075 df-xp 5120 df-rel 5121 df-cnv 5122 df-co 5123 df-dm 5124 df-rn 5125 df-res 5126 df-ima 5127 df-pred 5680 df-ord 5726 df-on 5727 df-lim 5728 df-suc 5729 df-iota 5851 df-fun 5890 df-fn 5891 df-f 5892 df-f1 5893 df-fo 5894 df-f1o 5895 df-fv 5896 df-riota 6611 df-ov 6653 df-oprab 6654 df-mpt2 6655 df-om 7066 df-1st 7168 df-2nd 7169 df-wrecs 7407 df-recs 7468 df-rdg 7506 df-1o 7560 df-2o 7561 df-oadd 7564 df-er 7742 df-map 7859 df-pm 7860 df-en 7956 df-dom 7957 df-sdom 7958 df-fin 7959 df-card 8765 df-cda 8990 df-pnf 10076 df-mnf 10077 df-xr 10078 df-ltxr 10079 df-le 10080 df-sub 10268 df-neg 10269 df-nn 11021 df-2 11079 df-3 11080 df-n0 11293 df-xnn0 11364 df-z 11378 df-uz 11688 df-rp 11833 df-fz 12327 df-fzo 12466 df-hash 13118 df-word 13299 df-lsw 13300 df-concat 13301 df-s1 13302 df-edg 25940 df-upgr 25977 df-umgr 25978 df-usgr 26046 df-nbgr 26228 df-clwwlks 26877 df-clwwlksn 26878

This theorem is referenced by: numclwlk1lem2foa 27224

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