Metamath Proof Explorer


Theorem usgr2pthlem

Description: Lemma for usgr2pth . (Contributed by Alexander van der Vekens, 27-Jan-2018) (Revised by AV, 5-Jun-2021)

Ref Expression
Hypotheses usgr2pthlem.v 𝑉 = ( Vtx ‘ 𝐺 )
usgr2pthlem.i 𝐼 = ( iEdg ‘ 𝐺 )
Assertion usgr2pthlem ( ( 𝐹 : ( 0 ..^ ( ♯ ‘ 𝐹 ) ) –1-1→ dom 𝐼𝑃 : ( 0 ... ( ♯ ‘ 𝐹 ) ) ⟶ 𝑉 ∧ ∀ 𝑖 ∈ ( 0 ..^ ( ♯ ‘ 𝐹 ) ) ( 𝐼 ‘ ( 𝐹𝑖 ) ) = { ( 𝑃𝑖 ) , ( 𝑃 ‘ ( 𝑖 + 1 ) ) } ) → ( ( 𝐺 ∈ USGraph ∧ ( ♯ ‘ 𝐹 ) = 2 ) → ∃ 𝑥𝑉𝑦 ∈ ( 𝑉 ∖ { 𝑥 } ) ∃ 𝑧 ∈ ( 𝑉 ∖ { 𝑥 , 𝑦 } ) ( ( ( 𝑃 ‘ 0 ) = 𝑥 ∧ ( 𝑃 ‘ 1 ) = 𝑦 ∧ ( 𝑃 ‘ 2 ) = 𝑧 ) ∧ ( ( 𝐼 ‘ ( 𝐹 ‘ 0 ) ) = { 𝑥 , 𝑦 } ∧ ( 𝐼 ‘ ( 𝐹 ‘ 1 ) ) = { 𝑦 , 𝑧 } ) ) ) )

Proof

Step Hyp Ref Expression
1 usgr2pthlem.v 𝑉 = ( Vtx ‘ 𝐺 )
2 usgr2pthlem.i 𝐼 = ( iEdg ‘ 𝐺 )
3 0nn0 0 ∈ ℕ0
4 2nn0 2 ∈ ℕ0
5 0le2 0 ≤ 2
6 elfz2nn0 ( 0 ∈ ( 0 ... 2 ) ↔ ( 0 ∈ ℕ0 ∧ 2 ∈ ℕ0 ∧ 0 ≤ 2 ) )
7 3 4 5 6 mpbir3an 0 ∈ ( 0 ... 2 )
8 ffvelcdm ( ( 𝑃 : ( 0 ... 2 ) ⟶ 𝑉 ∧ 0 ∈ ( 0 ... 2 ) ) → ( 𝑃 ‘ 0 ) ∈ 𝑉 )
9 7 8 mpan2 ( 𝑃 : ( 0 ... 2 ) ⟶ 𝑉 → ( 𝑃 ‘ 0 ) ∈ 𝑉 )
10 9 adantl ( ( ( ( 𝐹 : ( 0 ..^ 2 ) –1-1→ dom 𝐼 ∧ ( ( 𝐼 ‘ ( 𝐹 ‘ 0 ) ) = { ( 𝑃 ‘ 0 ) , ( 𝑃 ‘ 1 ) } ∧ ( 𝐼 ‘ ( 𝐹 ‘ 1 ) ) = { ( 𝑃 ‘ 1 ) , ( 𝑃 ‘ 2 ) } ) ) ∧ 𝐺 ∈ USGraph ) ∧ 𝑃 : ( 0 ... 2 ) ⟶ 𝑉 ) → ( 𝑃 ‘ 0 ) ∈ 𝑉 )
11 1nn0 1 ∈ ℕ0
12 1le2 1 ≤ 2
13 elfz2nn0 ( 1 ∈ ( 0 ... 2 ) ↔ ( 1 ∈ ℕ0 ∧ 2 ∈ ℕ0 ∧ 1 ≤ 2 ) )
14 11 4 12 13 mpbir3an 1 ∈ ( 0 ... 2 )
15 ffvelcdm ( ( 𝑃 : ( 0 ... 2 ) ⟶ 𝑉 ∧ 1 ∈ ( 0 ... 2 ) ) → ( 𝑃 ‘ 1 ) ∈ 𝑉 )
16 14 15 mpan2 ( 𝑃 : ( 0 ... 2 ) ⟶ 𝑉 → ( 𝑃 ‘ 1 ) ∈ 𝑉 )
17 16 adantl ( ( ( ( 𝐹 : ( 0 ..^ 2 ) –1-1→ dom 𝐼 ∧ ( ( 𝐼 ‘ ( 𝐹 ‘ 0 ) ) = { ( 𝑃 ‘ 0 ) , ( 𝑃 ‘ 1 ) } ∧ ( 𝐼 ‘ ( 𝐹 ‘ 1 ) ) = { ( 𝑃 ‘ 1 ) , ( 𝑃 ‘ 2 ) } ) ) ∧ 𝐺 ∈ USGraph ) ∧ 𝑃 : ( 0 ... 2 ) ⟶ 𝑉 ) → ( 𝑃 ‘ 1 ) ∈ 𝑉 )
18 simpr ( ( ( 𝐹 : ( 0 ..^ 2 ) –1-1→ dom 𝐼 ∧ ( ( 𝐼 ‘ ( 𝐹 ‘ 0 ) ) = { ( 𝑃 ‘ 0 ) , ( 𝑃 ‘ 1 ) } ∧ ( 𝐼 ‘ ( 𝐹 ‘ 1 ) ) = { ( 𝑃 ‘ 1 ) , ( 𝑃 ‘ 2 ) } ) ) ∧ 𝐺 ∈ USGraph ) → 𝐺 ∈ USGraph )
19 fvex ( 𝑃 ‘ 1 ) ∈ V
20 18 19 jctir ( ( ( 𝐹 : ( 0 ..^ 2 ) –1-1→ dom 𝐼 ∧ ( ( 𝐼 ‘ ( 𝐹 ‘ 0 ) ) = { ( 𝑃 ‘ 0 ) , ( 𝑃 ‘ 1 ) } ∧ ( 𝐼 ‘ ( 𝐹 ‘ 1 ) ) = { ( 𝑃 ‘ 1 ) , ( 𝑃 ‘ 2 ) } ) ) ∧ 𝐺 ∈ USGraph ) → ( 𝐺 ∈ USGraph ∧ ( 𝑃 ‘ 1 ) ∈ V ) )
21 prcom { ( 𝑃 ‘ 0 ) , ( 𝑃 ‘ 1 ) } = { ( 𝑃 ‘ 1 ) , ( 𝑃 ‘ 0 ) }
22 21 eqeq2i ( ( 𝐼 ‘ ( 𝐹 ‘ 0 ) ) = { ( 𝑃 ‘ 0 ) , ( 𝑃 ‘ 1 ) } ↔ ( 𝐼 ‘ ( 𝐹 ‘ 0 ) ) = { ( 𝑃 ‘ 1 ) , ( 𝑃 ‘ 0 ) } )
23 22 birani ( ( ( 𝐼 ‘ ( 𝐹 ‘ 0 ) ) = { ( 𝑃 ‘ 0 ) , ( 𝑃 ‘ 1 ) } ∧ ( 𝐼 ‘ ( 𝐹 ‘ 1 ) ) = { ( 𝑃 ‘ 1 ) , ( 𝑃 ‘ 2 ) } ) → ( 𝐼 ‘ ( 𝐹 ‘ 0 ) ) = { ( 𝑃 ‘ 1 ) , ( 𝑃 ‘ 0 ) } )
24 23 ad2antlr ( ( ( 𝐹 : ( 0 ..^ 2 ) –1-1→ dom 𝐼 ∧ ( ( 𝐼 ‘ ( 𝐹 ‘ 0 ) ) = { ( 𝑃 ‘ 0 ) , ( 𝑃 ‘ 1 ) } ∧ ( 𝐼 ‘ ( 𝐹 ‘ 1 ) ) = { ( 𝑃 ‘ 1 ) , ( 𝑃 ‘ 2 ) } ) ) ∧ 𝐺 ∈ USGraph ) → ( 𝐼 ‘ ( 𝐹 ‘ 0 ) ) = { ( 𝑃 ‘ 1 ) , ( 𝑃 ‘ 0 ) } )
25 2 usgrnloopv ( ( 𝐺 ∈ USGraph ∧ ( 𝑃 ‘ 1 ) ∈ V ) → ( ( 𝐼 ‘ ( 𝐹 ‘ 0 ) ) = { ( 𝑃 ‘ 1 ) , ( 𝑃 ‘ 0 ) } → ( 𝑃 ‘ 1 ) ≠ ( 𝑃 ‘ 0 ) ) )
26 20 24 25 sylc ( ( ( 𝐹 : ( 0 ..^ 2 ) –1-1→ dom 𝐼 ∧ ( ( 𝐼 ‘ ( 𝐹 ‘ 0 ) ) = { ( 𝑃 ‘ 0 ) , ( 𝑃 ‘ 1 ) } ∧ ( 𝐼 ‘ ( 𝐹 ‘ 1 ) ) = { ( 𝑃 ‘ 1 ) , ( 𝑃 ‘ 2 ) } ) ) ∧ 𝐺 ∈ USGraph ) → ( 𝑃 ‘ 1 ) ≠ ( 𝑃 ‘ 0 ) )
27 26 adantr ( ( ( ( 𝐹 : ( 0 ..^ 2 ) –1-1→ dom 𝐼 ∧ ( ( 𝐼 ‘ ( 𝐹 ‘ 0 ) ) = { ( 𝑃 ‘ 0 ) , ( 𝑃 ‘ 1 ) } ∧ ( 𝐼 ‘ ( 𝐹 ‘ 1 ) ) = { ( 𝑃 ‘ 1 ) , ( 𝑃 ‘ 2 ) } ) ) ∧ 𝐺 ∈ USGraph ) ∧ 𝑃 : ( 0 ... 2 ) ⟶ 𝑉 ) → ( 𝑃 ‘ 1 ) ≠ ( 𝑃 ‘ 0 ) )
28 19 elsn ( ( 𝑃 ‘ 1 ) ∈ { ( 𝑃 ‘ 0 ) } ↔ ( 𝑃 ‘ 1 ) = ( 𝑃 ‘ 0 ) )
29 28 necon3bbii ( ¬ ( 𝑃 ‘ 1 ) ∈ { ( 𝑃 ‘ 0 ) } ↔ ( 𝑃 ‘ 1 ) ≠ ( 𝑃 ‘ 0 ) )
30 27 29 sylibr ( ( ( ( 𝐹 : ( 0 ..^ 2 ) –1-1→ dom 𝐼 ∧ ( ( 𝐼 ‘ ( 𝐹 ‘ 0 ) ) = { ( 𝑃 ‘ 0 ) , ( 𝑃 ‘ 1 ) } ∧ ( 𝐼 ‘ ( 𝐹 ‘ 1 ) ) = { ( 𝑃 ‘ 1 ) , ( 𝑃 ‘ 2 ) } ) ) ∧ 𝐺 ∈ USGraph ) ∧ 𝑃 : ( 0 ... 2 ) ⟶ 𝑉 ) → ¬ ( 𝑃 ‘ 1 ) ∈ { ( 𝑃 ‘ 0 ) } )
31 17 30 eldifd ( ( ( ( 𝐹 : ( 0 ..^ 2 ) –1-1→ dom 𝐼 ∧ ( ( 𝐼 ‘ ( 𝐹 ‘ 0 ) ) = { ( 𝑃 ‘ 0 ) , ( 𝑃 ‘ 1 ) } ∧ ( 𝐼 ‘ ( 𝐹 ‘ 1 ) ) = { ( 𝑃 ‘ 1 ) , ( 𝑃 ‘ 2 ) } ) ) ∧ 𝐺 ∈ USGraph ) ∧ 𝑃 : ( 0 ... 2 ) ⟶ 𝑉 ) → ( 𝑃 ‘ 1 ) ∈ ( 𝑉 ∖ { ( 𝑃 ‘ 0 ) } ) )
32 31 adantr ( ( ( ( ( 𝐹 : ( 0 ..^ 2 ) –1-1→ dom 𝐼 ∧ ( ( 𝐼 ‘ ( 𝐹 ‘ 0 ) ) = { ( 𝑃 ‘ 0 ) , ( 𝑃 ‘ 1 ) } ∧ ( 𝐼 ‘ ( 𝐹 ‘ 1 ) ) = { ( 𝑃 ‘ 1 ) , ( 𝑃 ‘ 2 ) } ) ) ∧ 𝐺 ∈ USGraph ) ∧ 𝑃 : ( 0 ... 2 ) ⟶ 𝑉 ) ∧ 𝑥 = ( 𝑃 ‘ 0 ) ) → ( 𝑃 ‘ 1 ) ∈ ( 𝑉 ∖ { ( 𝑃 ‘ 0 ) } ) )
33 sneq ( 𝑥 = ( 𝑃 ‘ 0 ) → { 𝑥 } = { ( 𝑃 ‘ 0 ) } )
34 33 difeq2d ( 𝑥 = ( 𝑃 ‘ 0 ) → ( 𝑉 ∖ { 𝑥 } ) = ( 𝑉 ∖ { ( 𝑃 ‘ 0 ) } ) )
35 34 eleq2d ( 𝑥 = ( 𝑃 ‘ 0 ) → ( ( 𝑃 ‘ 1 ) ∈ ( 𝑉 ∖ { 𝑥 } ) ↔ ( 𝑃 ‘ 1 ) ∈ ( 𝑉 ∖ { ( 𝑃 ‘ 0 ) } ) ) )
36 35 adantl ( ( ( ( ( 𝐹 : ( 0 ..^ 2 ) –1-1→ dom 𝐼 ∧ ( ( 𝐼 ‘ ( 𝐹 ‘ 0 ) ) = { ( 𝑃 ‘ 0 ) , ( 𝑃 ‘ 1 ) } ∧ ( 𝐼 ‘ ( 𝐹 ‘ 1 ) ) = { ( 𝑃 ‘ 1 ) , ( 𝑃 ‘ 2 ) } ) ) ∧ 𝐺 ∈ USGraph ) ∧ 𝑃 : ( 0 ... 2 ) ⟶ 𝑉 ) ∧ 𝑥 = ( 𝑃 ‘ 0 ) ) → ( ( 𝑃 ‘ 1 ) ∈ ( 𝑉 ∖ { 𝑥 } ) ↔ ( 𝑃 ‘ 1 ) ∈ ( 𝑉 ∖ { ( 𝑃 ‘ 0 ) } ) ) )
37 32 36 mpbird ( ( ( ( ( 𝐹 : ( 0 ..^ 2 ) –1-1→ dom 𝐼 ∧ ( ( 𝐼 ‘ ( 𝐹 ‘ 0 ) ) = { ( 𝑃 ‘ 0 ) , ( 𝑃 ‘ 1 ) } ∧ ( 𝐼 ‘ ( 𝐹 ‘ 1 ) ) = { ( 𝑃 ‘ 1 ) , ( 𝑃 ‘ 2 ) } ) ) ∧ 𝐺 ∈ USGraph ) ∧ 𝑃 : ( 0 ... 2 ) ⟶ 𝑉 ) ∧ 𝑥 = ( 𝑃 ‘ 0 ) ) → ( 𝑃 ‘ 1 ) ∈ ( 𝑉 ∖ { 𝑥 } ) )
38 2re 2 ∈ ℝ
39 38 leidi 2 ≤ 2
40 elfz2nn0 ( 2 ∈ ( 0 ... 2 ) ↔ ( 2 ∈ ℕ0 ∧ 2 ∈ ℕ0 ∧ 2 ≤ 2 ) )
41 4 4 39 40 mpbir3an 2 ∈ ( 0 ... 2 )
42 ffvelcdm ( ( 𝑃 : ( 0 ... 2 ) ⟶ 𝑉 ∧ 2 ∈ ( 0 ... 2 ) ) → ( 𝑃 ‘ 2 ) ∈ 𝑉 )
43 41 42 mpan2 ( 𝑃 : ( 0 ... 2 ) ⟶ 𝑉 → ( 𝑃 ‘ 2 ) ∈ 𝑉 )
44 43 adantl ( ( ( ( 𝐹 : ( 0 ..^ 2 ) –1-1→ dom 𝐼 ∧ ( ( 𝐼 ‘ ( 𝐹 ‘ 0 ) ) = { ( 𝑃 ‘ 0 ) , ( 𝑃 ‘ 1 ) } ∧ ( 𝐼 ‘ ( 𝐹 ‘ 1 ) ) = { ( 𝑃 ‘ 1 ) , ( 𝑃 ‘ 2 ) } ) ) ∧ 𝐺 ∈ USGraph ) ∧ 𝑃 : ( 0 ... 2 ) ⟶ 𝑉 ) → ( 𝑃 ‘ 2 ) ∈ 𝑉 )
45 2 usgrf1 ( 𝐺 ∈ USGraph → 𝐼 : dom 𝐼1-1→ ran 𝐼 )
46 45 ad2antlr ( ( ( ( 𝐹 : ( 0 ..^ 2 ) –1-1→ dom 𝐼 ∧ ( ( 𝐼 ‘ ( 𝐹 ‘ 0 ) ) = { ( 𝑃 ‘ 0 ) , ( 𝑃 ‘ 1 ) } ∧ ( 𝐼 ‘ ( 𝐹 ‘ 1 ) ) = { ( 𝑃 ‘ 1 ) , ( 𝑃 ‘ 2 ) } ) ) ∧ 𝐺 ∈ USGraph ) ∧ 𝑃 : ( 0 ... 2 ) ⟶ 𝑉 ) → 𝐼 : dom 𝐼1-1→ ran 𝐼 )
47 simpl ( ( 𝐹 : ( 0 ..^ 2 ) –1-1→ dom 𝐼 ∧ ( ( 𝐼 ‘ ( 𝐹 ‘ 0 ) ) = { ( 𝑃 ‘ 0 ) , ( 𝑃 ‘ 1 ) } ∧ ( 𝐼 ‘ ( 𝐹 ‘ 1 ) ) = { ( 𝑃 ‘ 1 ) , ( 𝑃 ‘ 2 ) } ) ) → 𝐹 : ( 0 ..^ 2 ) –1-1→ dom 𝐼 )
48 47 ad2antrr ( ( ( ( 𝐹 : ( 0 ..^ 2 ) –1-1→ dom 𝐼 ∧ ( ( 𝐼 ‘ ( 𝐹 ‘ 0 ) ) = { ( 𝑃 ‘ 0 ) , ( 𝑃 ‘ 1 ) } ∧ ( 𝐼 ‘ ( 𝐹 ‘ 1 ) ) = { ( 𝑃 ‘ 1 ) , ( 𝑃 ‘ 2 ) } ) ) ∧ 𝐺 ∈ USGraph ) ∧ 𝑃 : ( 0 ... 2 ) ⟶ 𝑉 ) → 𝐹 : ( 0 ..^ 2 ) –1-1→ dom 𝐼 )
49 46 48 jca ( ( ( ( 𝐹 : ( 0 ..^ 2 ) –1-1→ dom 𝐼 ∧ ( ( 𝐼 ‘ ( 𝐹 ‘ 0 ) ) = { ( 𝑃 ‘ 0 ) , ( 𝑃 ‘ 1 ) } ∧ ( 𝐼 ‘ ( 𝐹 ‘ 1 ) ) = { ( 𝑃 ‘ 1 ) , ( 𝑃 ‘ 2 ) } ) ) ∧ 𝐺 ∈ USGraph ) ∧ 𝑃 : ( 0 ... 2 ) ⟶ 𝑉 ) → ( 𝐼 : dom 𝐼1-1→ ran 𝐼𝐹 : ( 0 ..^ 2 ) –1-1→ dom 𝐼 ) )
50 2nn 2 ∈ ℕ
51 lbfzo0 ( 0 ∈ ( 0 ..^ 2 ) ↔ 2 ∈ ℕ )
52 50 51 mpbir 0 ∈ ( 0 ..^ 2 )
53 1lt2 1 < 2
54 elfzo0 ( 1 ∈ ( 0 ..^ 2 ) ↔ ( 1 ∈ ℕ0 ∧ 2 ∈ ℕ ∧ 1 < 2 ) )
55 11 50 53 54 mpbir3an 1 ∈ ( 0 ..^ 2 )
56 52 55 pm3.2i ( 0 ∈ ( 0 ..^ 2 ) ∧ 1 ∈ ( 0 ..^ 2 ) )
57 56 a1i ( ( ( ( 𝐹 : ( 0 ..^ 2 ) –1-1→ dom 𝐼 ∧ ( ( 𝐼 ‘ ( 𝐹 ‘ 0 ) ) = { ( 𝑃 ‘ 0 ) , ( 𝑃 ‘ 1 ) } ∧ ( 𝐼 ‘ ( 𝐹 ‘ 1 ) ) = { ( 𝑃 ‘ 1 ) , ( 𝑃 ‘ 2 ) } ) ) ∧ 𝐺 ∈ USGraph ) ∧ 𝑃 : ( 0 ... 2 ) ⟶ 𝑉 ) → ( 0 ∈ ( 0 ..^ 2 ) ∧ 1 ∈ ( 0 ..^ 2 ) ) )
58 0ne1 0 ≠ 1
59 58 a1i ( ( ( ( 𝐹 : ( 0 ..^ 2 ) –1-1→ dom 𝐼 ∧ ( ( 𝐼 ‘ ( 𝐹 ‘ 0 ) ) = { ( 𝑃 ‘ 0 ) , ( 𝑃 ‘ 1 ) } ∧ ( 𝐼 ‘ ( 𝐹 ‘ 1 ) ) = { ( 𝑃 ‘ 1 ) , ( 𝑃 ‘ 2 ) } ) ) ∧ 𝐺 ∈ USGraph ) ∧ 𝑃 : ( 0 ... 2 ) ⟶ 𝑉 ) → 0 ≠ 1 )
60 49 57 59 3jca ( ( ( ( 𝐹 : ( 0 ..^ 2 ) –1-1→ dom 𝐼 ∧ ( ( 𝐼 ‘ ( 𝐹 ‘ 0 ) ) = { ( 𝑃 ‘ 0 ) , ( 𝑃 ‘ 1 ) } ∧ ( 𝐼 ‘ ( 𝐹 ‘ 1 ) ) = { ( 𝑃 ‘ 1 ) , ( 𝑃 ‘ 2 ) } ) ) ∧ 𝐺 ∈ USGraph ) ∧ 𝑃 : ( 0 ... 2 ) ⟶ 𝑉 ) → ( ( 𝐼 : dom 𝐼1-1→ ran 𝐼𝐹 : ( 0 ..^ 2 ) –1-1→ dom 𝐼 ) ∧ ( 0 ∈ ( 0 ..^ 2 ) ∧ 1 ∈ ( 0 ..^ 2 ) ) ∧ 0 ≠ 1 ) )
61 simpr ( ( 𝐹 : ( 0 ..^ 2 ) –1-1→ dom 𝐼 ∧ ( ( 𝐼 ‘ ( 𝐹 ‘ 0 ) ) = { ( 𝑃 ‘ 0 ) , ( 𝑃 ‘ 1 ) } ∧ ( 𝐼 ‘ ( 𝐹 ‘ 1 ) ) = { ( 𝑃 ‘ 1 ) , ( 𝑃 ‘ 2 ) } ) ) → ( ( 𝐼 ‘ ( 𝐹 ‘ 0 ) ) = { ( 𝑃 ‘ 0 ) , ( 𝑃 ‘ 1 ) } ∧ ( 𝐼 ‘ ( 𝐹 ‘ 1 ) ) = { ( 𝑃 ‘ 1 ) , ( 𝑃 ‘ 2 ) } ) )
62 61 ad2antrr ( ( ( ( 𝐹 : ( 0 ..^ 2 ) –1-1→ dom 𝐼 ∧ ( ( 𝐼 ‘ ( 𝐹 ‘ 0 ) ) = { ( 𝑃 ‘ 0 ) , ( 𝑃 ‘ 1 ) } ∧ ( 𝐼 ‘ ( 𝐹 ‘ 1 ) ) = { ( 𝑃 ‘ 1 ) , ( 𝑃 ‘ 2 ) } ) ) ∧ 𝐺 ∈ USGraph ) ∧ 𝑃 : ( 0 ... 2 ) ⟶ 𝑉 ) → ( ( 𝐼 ‘ ( 𝐹 ‘ 0 ) ) = { ( 𝑃 ‘ 0 ) , ( 𝑃 ‘ 1 ) } ∧ ( 𝐼 ‘ ( 𝐹 ‘ 1 ) ) = { ( 𝑃 ‘ 1 ) , ( 𝑃 ‘ 2 ) } ) )
63 2f1fvneq ( ( ( 𝐼 : dom 𝐼1-1→ ran 𝐼𝐹 : ( 0 ..^ 2 ) –1-1→ dom 𝐼 ) ∧ ( 0 ∈ ( 0 ..^ 2 ) ∧ 1 ∈ ( 0 ..^ 2 ) ) ∧ 0 ≠ 1 ) → ( ( ( 𝐼 ‘ ( 𝐹 ‘ 0 ) ) = { ( 𝑃 ‘ 0 ) , ( 𝑃 ‘ 1 ) } ∧ ( 𝐼 ‘ ( 𝐹 ‘ 1 ) ) = { ( 𝑃 ‘ 1 ) , ( 𝑃 ‘ 2 ) } ) → { ( 𝑃 ‘ 0 ) , ( 𝑃 ‘ 1 ) } ≠ { ( 𝑃 ‘ 1 ) , ( 𝑃 ‘ 2 ) } ) )
64 60 62 63 sylc ( ( ( ( 𝐹 : ( 0 ..^ 2 ) –1-1→ dom 𝐼 ∧ ( ( 𝐼 ‘ ( 𝐹 ‘ 0 ) ) = { ( 𝑃 ‘ 0 ) , ( 𝑃 ‘ 1 ) } ∧ ( 𝐼 ‘ ( 𝐹 ‘ 1 ) ) = { ( 𝑃 ‘ 1 ) , ( 𝑃 ‘ 2 ) } ) ) ∧ 𝐺 ∈ USGraph ) ∧ 𝑃 : ( 0 ... 2 ) ⟶ 𝑉 ) → { ( 𝑃 ‘ 0 ) , ( 𝑃 ‘ 1 ) } ≠ { ( 𝑃 ‘ 1 ) , ( 𝑃 ‘ 2 ) } )
65 necom ( ( 𝑃 ‘ 2 ) ≠ ( 𝑃 ‘ 0 ) ↔ ( 𝑃 ‘ 0 ) ≠ ( 𝑃 ‘ 2 ) )
66 fvex ( 𝑃 ‘ 0 ) ∈ V
67 fvex ( 𝑃 ‘ 2 ) ∈ V
68 66 19 67 3pm3.2i ( ( 𝑃 ‘ 0 ) ∈ V ∧ ( 𝑃 ‘ 1 ) ∈ V ∧ ( 𝑃 ‘ 2 ) ∈ V )
69 fvexd ( ( ( 𝐹 : ( 0 ..^ 2 ) –1-1→ dom 𝐼 ∧ ( ( 𝐼 ‘ ( 𝐹 ‘ 0 ) ) = { ( 𝑃 ‘ 0 ) , ( 𝑃 ‘ 1 ) } ∧ ( 𝐼 ‘ ( 𝐹 ‘ 1 ) ) = { ( 𝑃 ‘ 1 ) , ( 𝑃 ‘ 2 ) } ) ) ∧ 𝐺 ∈ USGraph ) → ( 𝑃 ‘ 0 ) ∈ V )
70 simpl ( ( ( 𝐼 ‘ ( 𝐹 ‘ 0 ) ) = { ( 𝑃 ‘ 0 ) , ( 𝑃 ‘ 1 ) } ∧ ( 𝐼 ‘ ( 𝐹 ‘ 1 ) ) = { ( 𝑃 ‘ 1 ) , ( 𝑃 ‘ 2 ) } ) → ( 𝐼 ‘ ( 𝐹 ‘ 0 ) ) = { ( 𝑃 ‘ 0 ) , ( 𝑃 ‘ 1 ) } )
71 70 ad2antlr ( ( ( 𝐹 : ( 0 ..^ 2 ) –1-1→ dom 𝐼 ∧ ( ( 𝐼 ‘ ( 𝐹 ‘ 0 ) ) = { ( 𝑃 ‘ 0 ) , ( 𝑃 ‘ 1 ) } ∧ ( 𝐼 ‘ ( 𝐹 ‘ 1 ) ) = { ( 𝑃 ‘ 1 ) , ( 𝑃 ‘ 2 ) } ) ) ∧ 𝐺 ∈ USGraph ) → ( 𝐼 ‘ ( 𝐹 ‘ 0 ) ) = { ( 𝑃 ‘ 0 ) , ( 𝑃 ‘ 1 ) } )
72 18 69 71 jca31 ( ( ( 𝐹 : ( 0 ..^ 2 ) –1-1→ dom 𝐼 ∧ ( ( 𝐼 ‘ ( 𝐹 ‘ 0 ) ) = { ( 𝑃 ‘ 0 ) , ( 𝑃 ‘ 1 ) } ∧ ( 𝐼 ‘ ( 𝐹 ‘ 1 ) ) = { ( 𝑃 ‘ 1 ) , ( 𝑃 ‘ 2 ) } ) ) ∧ 𝐺 ∈ USGraph ) → ( ( 𝐺 ∈ USGraph ∧ ( 𝑃 ‘ 0 ) ∈ V ) ∧ ( 𝐼 ‘ ( 𝐹 ‘ 0 ) ) = { ( 𝑃 ‘ 0 ) , ( 𝑃 ‘ 1 ) } ) )
73 72 adantr ( ( ( ( 𝐹 : ( 0 ..^ 2 ) –1-1→ dom 𝐼 ∧ ( ( 𝐼 ‘ ( 𝐹 ‘ 0 ) ) = { ( 𝑃 ‘ 0 ) , ( 𝑃 ‘ 1 ) } ∧ ( 𝐼 ‘ ( 𝐹 ‘ 1 ) ) = { ( 𝑃 ‘ 1 ) , ( 𝑃 ‘ 2 ) } ) ) ∧ 𝐺 ∈ USGraph ) ∧ 𝑃 : ( 0 ... 2 ) ⟶ 𝑉 ) → ( ( 𝐺 ∈ USGraph ∧ ( 𝑃 ‘ 0 ) ∈ V ) ∧ ( 𝐼 ‘ ( 𝐹 ‘ 0 ) ) = { ( 𝑃 ‘ 0 ) , ( 𝑃 ‘ 1 ) } ) )
74 2 usgrnloopv ( ( 𝐺 ∈ USGraph ∧ ( 𝑃 ‘ 0 ) ∈ V ) → ( ( 𝐼 ‘ ( 𝐹 ‘ 0 ) ) = { ( 𝑃 ‘ 0 ) , ( 𝑃 ‘ 1 ) } → ( 𝑃 ‘ 0 ) ≠ ( 𝑃 ‘ 1 ) ) )
75 74 imp ( ( ( 𝐺 ∈ USGraph ∧ ( 𝑃 ‘ 0 ) ∈ V ) ∧ ( 𝐼 ‘ ( 𝐹 ‘ 0 ) ) = { ( 𝑃 ‘ 0 ) , ( 𝑃 ‘ 1 ) } ) → ( 𝑃 ‘ 0 ) ≠ ( 𝑃 ‘ 1 ) )
76 73 75 syl ( ( ( ( 𝐹 : ( 0 ..^ 2 ) –1-1→ dom 𝐼 ∧ ( ( 𝐼 ‘ ( 𝐹 ‘ 0 ) ) = { ( 𝑃 ‘ 0 ) , ( 𝑃 ‘ 1 ) } ∧ ( 𝐼 ‘ ( 𝐹 ‘ 1 ) ) = { ( 𝑃 ‘ 1 ) , ( 𝑃 ‘ 2 ) } ) ) ∧ 𝐺 ∈ USGraph ) ∧ 𝑃 : ( 0 ... 2 ) ⟶ 𝑉 ) → ( 𝑃 ‘ 0 ) ≠ ( 𝑃 ‘ 1 ) )
77 pr1nebg ( ( ( ( 𝑃 ‘ 0 ) ∈ V ∧ ( 𝑃 ‘ 1 ) ∈ V ∧ ( 𝑃 ‘ 2 ) ∈ V ) ∧ ( 𝑃 ‘ 0 ) ≠ ( 𝑃 ‘ 1 ) ) → ( ( 𝑃 ‘ 0 ) ≠ ( 𝑃 ‘ 2 ) ↔ { ( 𝑃 ‘ 0 ) , ( 𝑃 ‘ 1 ) } ≠ { ( 𝑃 ‘ 1 ) , ( 𝑃 ‘ 2 ) } ) )
78 68 76 77 sylancr ( ( ( ( 𝐹 : ( 0 ..^ 2 ) –1-1→ dom 𝐼 ∧ ( ( 𝐼 ‘ ( 𝐹 ‘ 0 ) ) = { ( 𝑃 ‘ 0 ) , ( 𝑃 ‘ 1 ) } ∧ ( 𝐼 ‘ ( 𝐹 ‘ 1 ) ) = { ( 𝑃 ‘ 1 ) , ( 𝑃 ‘ 2 ) } ) ) ∧ 𝐺 ∈ USGraph ) ∧ 𝑃 : ( 0 ... 2 ) ⟶ 𝑉 ) → ( ( 𝑃 ‘ 0 ) ≠ ( 𝑃 ‘ 2 ) ↔ { ( 𝑃 ‘ 0 ) , ( 𝑃 ‘ 1 ) } ≠ { ( 𝑃 ‘ 1 ) , ( 𝑃 ‘ 2 ) } ) )
79 65 78 bitrid ( ( ( ( 𝐹 : ( 0 ..^ 2 ) –1-1→ dom 𝐼 ∧ ( ( 𝐼 ‘ ( 𝐹 ‘ 0 ) ) = { ( 𝑃 ‘ 0 ) , ( 𝑃 ‘ 1 ) } ∧ ( 𝐼 ‘ ( 𝐹 ‘ 1 ) ) = { ( 𝑃 ‘ 1 ) , ( 𝑃 ‘ 2 ) } ) ) ∧ 𝐺 ∈ USGraph ) ∧ 𝑃 : ( 0 ... 2 ) ⟶ 𝑉 ) → ( ( 𝑃 ‘ 2 ) ≠ ( 𝑃 ‘ 0 ) ↔ { ( 𝑃 ‘ 0 ) , ( 𝑃 ‘ 1 ) } ≠ { ( 𝑃 ‘ 1 ) , ( 𝑃 ‘ 2 ) } ) )
80 64 79 mpbird ( ( ( ( 𝐹 : ( 0 ..^ 2 ) –1-1→ dom 𝐼 ∧ ( ( 𝐼 ‘ ( 𝐹 ‘ 0 ) ) = { ( 𝑃 ‘ 0 ) , ( 𝑃 ‘ 1 ) } ∧ ( 𝐼 ‘ ( 𝐹 ‘ 1 ) ) = { ( 𝑃 ‘ 1 ) , ( 𝑃 ‘ 2 ) } ) ) ∧ 𝐺 ∈ USGraph ) ∧ 𝑃 : ( 0 ... 2 ) ⟶ 𝑉 ) → ( 𝑃 ‘ 2 ) ≠ ( 𝑃 ‘ 0 ) )
81 fvexd ( ( ( 𝐹 : ( 0 ..^ 2 ) –1-1→ dom 𝐼 ∧ ( ( 𝐼 ‘ ( 𝐹 ‘ 0 ) ) = { ( 𝑃 ‘ 0 ) , ( 𝑃 ‘ 1 ) } ∧ ( 𝐼 ‘ ( 𝐹 ‘ 1 ) ) = { ( 𝑃 ‘ 1 ) , ( 𝑃 ‘ 2 ) } ) ) ∧ 𝐺 ∈ USGraph ) → ( 𝑃 ‘ 2 ) ∈ V )
82 prcom { ( 𝑃 ‘ 1 ) , ( 𝑃 ‘ 2 ) } = { ( 𝑃 ‘ 2 ) , ( 𝑃 ‘ 1 ) }
83 82 eqeq2i ( ( 𝐼 ‘ ( 𝐹 ‘ 1 ) ) = { ( 𝑃 ‘ 1 ) , ( 𝑃 ‘ 2 ) } ↔ ( 𝐼 ‘ ( 𝐹 ‘ 1 ) ) = { ( 𝑃 ‘ 2 ) , ( 𝑃 ‘ 1 ) } )
84 83 bilani ( ( ( 𝐼 ‘ ( 𝐹 ‘ 0 ) ) = { ( 𝑃 ‘ 0 ) , ( 𝑃 ‘ 1 ) } ∧ ( 𝐼 ‘ ( 𝐹 ‘ 1 ) ) = { ( 𝑃 ‘ 1 ) , ( 𝑃 ‘ 2 ) } ) → ( 𝐼 ‘ ( 𝐹 ‘ 1 ) ) = { ( 𝑃 ‘ 2 ) , ( 𝑃 ‘ 1 ) } )
85 84 ad2antlr ( ( ( 𝐹 : ( 0 ..^ 2 ) –1-1→ dom 𝐼 ∧ ( ( 𝐼 ‘ ( 𝐹 ‘ 0 ) ) = { ( 𝑃 ‘ 0 ) , ( 𝑃 ‘ 1 ) } ∧ ( 𝐼 ‘ ( 𝐹 ‘ 1 ) ) = { ( 𝑃 ‘ 1 ) , ( 𝑃 ‘ 2 ) } ) ) ∧ 𝐺 ∈ USGraph ) → ( 𝐼 ‘ ( 𝐹 ‘ 1 ) ) = { ( 𝑃 ‘ 2 ) , ( 𝑃 ‘ 1 ) } )
86 18 81 85 jca31 ( ( ( 𝐹 : ( 0 ..^ 2 ) –1-1→ dom 𝐼 ∧ ( ( 𝐼 ‘ ( 𝐹 ‘ 0 ) ) = { ( 𝑃 ‘ 0 ) , ( 𝑃 ‘ 1 ) } ∧ ( 𝐼 ‘ ( 𝐹 ‘ 1 ) ) = { ( 𝑃 ‘ 1 ) , ( 𝑃 ‘ 2 ) } ) ) ∧ 𝐺 ∈ USGraph ) → ( ( 𝐺 ∈ USGraph ∧ ( 𝑃 ‘ 2 ) ∈ V ) ∧ ( 𝐼 ‘ ( 𝐹 ‘ 1 ) ) = { ( 𝑃 ‘ 2 ) , ( 𝑃 ‘ 1 ) } ) )
87 86 adantr ( ( ( ( 𝐹 : ( 0 ..^ 2 ) –1-1→ dom 𝐼 ∧ ( ( 𝐼 ‘ ( 𝐹 ‘ 0 ) ) = { ( 𝑃 ‘ 0 ) , ( 𝑃 ‘ 1 ) } ∧ ( 𝐼 ‘ ( 𝐹 ‘ 1 ) ) = { ( 𝑃 ‘ 1 ) , ( 𝑃 ‘ 2 ) } ) ) ∧ 𝐺 ∈ USGraph ) ∧ 𝑃 : ( 0 ... 2 ) ⟶ 𝑉 ) → ( ( 𝐺 ∈ USGraph ∧ ( 𝑃 ‘ 2 ) ∈ V ) ∧ ( 𝐼 ‘ ( 𝐹 ‘ 1 ) ) = { ( 𝑃 ‘ 2 ) , ( 𝑃 ‘ 1 ) } ) )
88 2 usgrnloopv ( ( 𝐺 ∈ USGraph ∧ ( 𝑃 ‘ 2 ) ∈ V ) → ( ( 𝐼 ‘ ( 𝐹 ‘ 1 ) ) = { ( 𝑃 ‘ 2 ) , ( 𝑃 ‘ 1 ) } → ( 𝑃 ‘ 2 ) ≠ ( 𝑃 ‘ 1 ) ) )
89 88 imp ( ( ( 𝐺 ∈ USGraph ∧ ( 𝑃 ‘ 2 ) ∈ V ) ∧ ( 𝐼 ‘ ( 𝐹 ‘ 1 ) ) = { ( 𝑃 ‘ 2 ) , ( 𝑃 ‘ 1 ) } ) → ( 𝑃 ‘ 2 ) ≠ ( 𝑃 ‘ 1 ) )
90 87 89 syl ( ( ( ( 𝐹 : ( 0 ..^ 2 ) –1-1→ dom 𝐼 ∧ ( ( 𝐼 ‘ ( 𝐹 ‘ 0 ) ) = { ( 𝑃 ‘ 0 ) , ( 𝑃 ‘ 1 ) } ∧ ( 𝐼 ‘ ( 𝐹 ‘ 1 ) ) = { ( 𝑃 ‘ 1 ) , ( 𝑃 ‘ 2 ) } ) ) ∧ 𝐺 ∈ USGraph ) ∧ 𝑃 : ( 0 ... 2 ) ⟶ 𝑉 ) → ( 𝑃 ‘ 2 ) ≠ ( 𝑃 ‘ 1 ) )
91 80 90 nelprd ( ( ( ( 𝐹 : ( 0 ..^ 2 ) –1-1→ dom 𝐼 ∧ ( ( 𝐼 ‘ ( 𝐹 ‘ 0 ) ) = { ( 𝑃 ‘ 0 ) , ( 𝑃 ‘ 1 ) } ∧ ( 𝐼 ‘ ( 𝐹 ‘ 1 ) ) = { ( 𝑃 ‘ 1 ) , ( 𝑃 ‘ 2 ) } ) ) ∧ 𝐺 ∈ USGraph ) ∧ 𝑃 : ( 0 ... 2 ) ⟶ 𝑉 ) → ¬ ( 𝑃 ‘ 2 ) ∈ { ( 𝑃 ‘ 0 ) , ( 𝑃 ‘ 1 ) } )
92 44 91 eldifd ( ( ( ( 𝐹 : ( 0 ..^ 2 ) –1-1→ dom 𝐼 ∧ ( ( 𝐼 ‘ ( 𝐹 ‘ 0 ) ) = { ( 𝑃 ‘ 0 ) , ( 𝑃 ‘ 1 ) } ∧ ( 𝐼 ‘ ( 𝐹 ‘ 1 ) ) = { ( 𝑃 ‘ 1 ) , ( 𝑃 ‘ 2 ) } ) ) ∧ 𝐺 ∈ USGraph ) ∧ 𝑃 : ( 0 ... 2 ) ⟶ 𝑉 ) → ( 𝑃 ‘ 2 ) ∈ ( 𝑉 ∖ { ( 𝑃 ‘ 0 ) , ( 𝑃 ‘ 1 ) } ) )
93 92 ad2antrr ( ( ( ( ( ( 𝐹 : ( 0 ..^ 2 ) –1-1→ dom 𝐼 ∧ ( ( 𝐼 ‘ ( 𝐹 ‘ 0 ) ) = { ( 𝑃 ‘ 0 ) , ( 𝑃 ‘ 1 ) } ∧ ( 𝐼 ‘ ( 𝐹 ‘ 1 ) ) = { ( 𝑃 ‘ 1 ) , ( 𝑃 ‘ 2 ) } ) ) ∧ 𝐺 ∈ USGraph ) ∧ 𝑃 : ( 0 ... 2 ) ⟶ 𝑉 ) ∧ 𝑥 = ( 𝑃 ‘ 0 ) ) ∧ 𝑦 = ( 𝑃 ‘ 1 ) ) → ( 𝑃 ‘ 2 ) ∈ ( 𝑉 ∖ { ( 𝑃 ‘ 0 ) , ( 𝑃 ‘ 1 ) } ) )
94 preq12 ( ( 𝑥 = ( 𝑃 ‘ 0 ) ∧ 𝑦 = ( 𝑃 ‘ 1 ) ) → { 𝑥 , 𝑦 } = { ( 𝑃 ‘ 0 ) , ( 𝑃 ‘ 1 ) } )
95 94 difeq2d ( ( 𝑥 = ( 𝑃 ‘ 0 ) ∧ 𝑦 = ( 𝑃 ‘ 1 ) ) → ( 𝑉 ∖ { 𝑥 , 𝑦 } ) = ( 𝑉 ∖ { ( 𝑃 ‘ 0 ) , ( 𝑃 ‘ 1 ) } ) )
96 95 eleq2d ( ( 𝑥 = ( 𝑃 ‘ 0 ) ∧ 𝑦 = ( 𝑃 ‘ 1 ) ) → ( ( 𝑃 ‘ 2 ) ∈ ( 𝑉 ∖ { 𝑥 , 𝑦 } ) ↔ ( 𝑃 ‘ 2 ) ∈ ( 𝑉 ∖ { ( 𝑃 ‘ 0 ) , ( 𝑃 ‘ 1 ) } ) ) )
97 96 adantll ( ( ( ( ( ( 𝐹 : ( 0 ..^ 2 ) –1-1→ dom 𝐼 ∧ ( ( 𝐼 ‘ ( 𝐹 ‘ 0 ) ) = { ( 𝑃 ‘ 0 ) , ( 𝑃 ‘ 1 ) } ∧ ( 𝐼 ‘ ( 𝐹 ‘ 1 ) ) = { ( 𝑃 ‘ 1 ) , ( 𝑃 ‘ 2 ) } ) ) ∧ 𝐺 ∈ USGraph ) ∧ 𝑃 : ( 0 ... 2 ) ⟶ 𝑉 ) ∧ 𝑥 = ( 𝑃 ‘ 0 ) ) ∧ 𝑦 = ( 𝑃 ‘ 1 ) ) → ( ( 𝑃 ‘ 2 ) ∈ ( 𝑉 ∖ { 𝑥 , 𝑦 } ) ↔ ( 𝑃 ‘ 2 ) ∈ ( 𝑉 ∖ { ( 𝑃 ‘ 0 ) , ( 𝑃 ‘ 1 ) } ) ) )
98 93 97 mpbird ( ( ( ( ( ( 𝐹 : ( 0 ..^ 2 ) –1-1→ dom 𝐼 ∧ ( ( 𝐼 ‘ ( 𝐹 ‘ 0 ) ) = { ( 𝑃 ‘ 0 ) , ( 𝑃 ‘ 1 ) } ∧ ( 𝐼 ‘ ( 𝐹 ‘ 1 ) ) = { ( 𝑃 ‘ 1 ) , ( 𝑃 ‘ 2 ) } ) ) ∧ 𝐺 ∈ USGraph ) ∧ 𝑃 : ( 0 ... 2 ) ⟶ 𝑉 ) ∧ 𝑥 = ( 𝑃 ‘ 0 ) ) ∧ 𝑦 = ( 𝑃 ‘ 1 ) ) → ( 𝑃 ‘ 2 ) ∈ ( 𝑉 ∖ { 𝑥 , 𝑦 } ) )
99 eqcom ( 𝑥 = ( 𝑃 ‘ 0 ) ↔ ( 𝑃 ‘ 0 ) = 𝑥 )
100 eqcom ( 𝑦 = ( 𝑃 ‘ 1 ) ↔ ( 𝑃 ‘ 1 ) = 𝑦 )
101 eqcom ( 𝑧 = ( 𝑃 ‘ 2 ) ↔ ( 𝑃 ‘ 2 ) = 𝑧 )
102 99 100 101 3anbi123i ( ( 𝑥 = ( 𝑃 ‘ 0 ) ∧ 𝑦 = ( 𝑃 ‘ 1 ) ∧ 𝑧 = ( 𝑃 ‘ 2 ) ) ↔ ( ( 𝑃 ‘ 0 ) = 𝑥 ∧ ( 𝑃 ‘ 1 ) = 𝑦 ∧ ( 𝑃 ‘ 2 ) = 𝑧 ) )
103 102 biimpi ( ( 𝑥 = ( 𝑃 ‘ 0 ) ∧ 𝑦 = ( 𝑃 ‘ 1 ) ∧ 𝑧 = ( 𝑃 ‘ 2 ) ) → ( ( 𝑃 ‘ 0 ) = 𝑥 ∧ ( 𝑃 ‘ 1 ) = 𝑦 ∧ ( 𝑃 ‘ 2 ) = 𝑧 ) )
104 103 ad4ant123 ( ( ( ( 𝑥 = ( 𝑃 ‘ 0 ) ∧ 𝑦 = ( 𝑃 ‘ 1 ) ) ∧ 𝑧 = ( 𝑃 ‘ 2 ) ) ∧ ( ( 𝐼 ‘ ( 𝐹 ‘ 0 ) ) = { ( 𝑃 ‘ 0 ) , ( 𝑃 ‘ 1 ) } ∧ ( 𝐼 ‘ ( 𝐹 ‘ 1 ) ) = { ( 𝑃 ‘ 1 ) , ( 𝑃 ‘ 2 ) } ) ) → ( ( 𝑃 ‘ 0 ) = 𝑥 ∧ ( 𝑃 ‘ 1 ) = 𝑦 ∧ ( 𝑃 ‘ 2 ) = 𝑧 ) )
105 99 biimpi ( 𝑥 = ( 𝑃 ‘ 0 ) → ( 𝑃 ‘ 0 ) = 𝑥 )
106 105 ad2antrr ( ( ( 𝑥 = ( 𝑃 ‘ 0 ) ∧ 𝑦 = ( 𝑃 ‘ 1 ) ) ∧ 𝑧 = ( 𝑃 ‘ 2 ) ) → ( 𝑃 ‘ 0 ) = 𝑥 )
107 100 biimpi ( 𝑦 = ( 𝑃 ‘ 1 ) → ( 𝑃 ‘ 1 ) = 𝑦 )
108 107 ad2antlr ( ( ( 𝑥 = ( 𝑃 ‘ 0 ) ∧ 𝑦 = ( 𝑃 ‘ 1 ) ) ∧ 𝑧 = ( 𝑃 ‘ 2 ) ) → ( 𝑃 ‘ 1 ) = 𝑦 )
109 106 108 preq12d ( ( ( 𝑥 = ( 𝑃 ‘ 0 ) ∧ 𝑦 = ( 𝑃 ‘ 1 ) ) ∧ 𝑧 = ( 𝑃 ‘ 2 ) ) → { ( 𝑃 ‘ 0 ) , ( 𝑃 ‘ 1 ) } = { 𝑥 , 𝑦 } )
110 109 eqeq2d ( ( ( 𝑥 = ( 𝑃 ‘ 0 ) ∧ 𝑦 = ( 𝑃 ‘ 1 ) ) ∧ 𝑧 = ( 𝑃 ‘ 2 ) ) → ( ( 𝐼 ‘ ( 𝐹 ‘ 0 ) ) = { ( 𝑃 ‘ 0 ) , ( 𝑃 ‘ 1 ) } ↔ ( 𝐼 ‘ ( 𝐹 ‘ 0 ) ) = { 𝑥 , 𝑦 } ) )
111 101 bilani ( ( ( 𝑥 = ( 𝑃 ‘ 0 ) ∧ 𝑦 = ( 𝑃 ‘ 1 ) ) ∧ 𝑧 = ( 𝑃 ‘ 2 ) ) → ( 𝑃 ‘ 2 ) = 𝑧 )
112 108 111 preq12d ( ( ( 𝑥 = ( 𝑃 ‘ 0 ) ∧ 𝑦 = ( 𝑃 ‘ 1 ) ) ∧ 𝑧 = ( 𝑃 ‘ 2 ) ) → { ( 𝑃 ‘ 1 ) , ( 𝑃 ‘ 2 ) } = { 𝑦 , 𝑧 } )
113 112 eqeq2d ( ( ( 𝑥 = ( 𝑃 ‘ 0 ) ∧ 𝑦 = ( 𝑃 ‘ 1 ) ) ∧ 𝑧 = ( 𝑃 ‘ 2 ) ) → ( ( 𝐼 ‘ ( 𝐹 ‘ 1 ) ) = { ( 𝑃 ‘ 1 ) , ( 𝑃 ‘ 2 ) } ↔ ( 𝐼 ‘ ( 𝐹 ‘ 1 ) ) = { 𝑦 , 𝑧 } ) )
114 110 113 anbi12d ( ( ( 𝑥 = ( 𝑃 ‘ 0 ) ∧ 𝑦 = ( 𝑃 ‘ 1 ) ) ∧ 𝑧 = ( 𝑃 ‘ 2 ) ) → ( ( ( 𝐼 ‘ ( 𝐹 ‘ 0 ) ) = { ( 𝑃 ‘ 0 ) , ( 𝑃 ‘ 1 ) } ∧ ( 𝐼 ‘ ( 𝐹 ‘ 1 ) ) = { ( 𝑃 ‘ 1 ) , ( 𝑃 ‘ 2 ) } ) ↔ ( ( 𝐼 ‘ ( 𝐹 ‘ 0 ) ) = { 𝑥 , 𝑦 } ∧ ( 𝐼 ‘ ( 𝐹 ‘ 1 ) ) = { 𝑦 , 𝑧 } ) ) )
115 114 biimpa ( ( ( ( 𝑥 = ( 𝑃 ‘ 0 ) ∧ 𝑦 = ( 𝑃 ‘ 1 ) ) ∧ 𝑧 = ( 𝑃 ‘ 2 ) ) ∧ ( ( 𝐼 ‘ ( 𝐹 ‘ 0 ) ) = { ( 𝑃 ‘ 0 ) , ( 𝑃 ‘ 1 ) } ∧ ( 𝐼 ‘ ( 𝐹 ‘ 1 ) ) = { ( 𝑃 ‘ 1 ) , ( 𝑃 ‘ 2 ) } ) ) → ( ( 𝐼 ‘ ( 𝐹 ‘ 0 ) ) = { 𝑥 , 𝑦 } ∧ ( 𝐼 ‘ ( 𝐹 ‘ 1 ) ) = { 𝑦 , 𝑧 } ) )
116 104 115 jca ( ( ( ( 𝑥 = ( 𝑃 ‘ 0 ) ∧ 𝑦 = ( 𝑃 ‘ 1 ) ) ∧ 𝑧 = ( 𝑃 ‘ 2 ) ) ∧ ( ( 𝐼 ‘ ( 𝐹 ‘ 0 ) ) = { ( 𝑃 ‘ 0 ) , ( 𝑃 ‘ 1 ) } ∧ ( 𝐼 ‘ ( 𝐹 ‘ 1 ) ) = { ( 𝑃 ‘ 1 ) , ( 𝑃 ‘ 2 ) } ) ) → ( ( ( 𝑃 ‘ 0 ) = 𝑥 ∧ ( 𝑃 ‘ 1 ) = 𝑦 ∧ ( 𝑃 ‘ 2 ) = 𝑧 ) ∧ ( ( 𝐼 ‘ ( 𝐹 ‘ 0 ) ) = { 𝑥 , 𝑦 } ∧ ( 𝐼 ‘ ( 𝐹 ‘ 1 ) ) = { 𝑦 , 𝑧 } ) ) )
117 116 exp41 ( 𝑥 = ( 𝑃 ‘ 0 ) → ( 𝑦 = ( 𝑃 ‘ 1 ) → ( 𝑧 = ( 𝑃 ‘ 2 ) → ( ( ( 𝐼 ‘ ( 𝐹 ‘ 0 ) ) = { ( 𝑃 ‘ 0 ) , ( 𝑃 ‘ 1 ) } ∧ ( 𝐼 ‘ ( 𝐹 ‘ 1 ) ) = { ( 𝑃 ‘ 1 ) , ( 𝑃 ‘ 2 ) } ) → ( ( ( 𝑃 ‘ 0 ) = 𝑥 ∧ ( 𝑃 ‘ 1 ) = 𝑦 ∧ ( 𝑃 ‘ 2 ) = 𝑧 ) ∧ ( ( 𝐼 ‘ ( 𝐹 ‘ 0 ) ) = { 𝑥 , 𝑦 } ∧ ( 𝐼 ‘ ( 𝐹 ‘ 1 ) ) = { 𝑦 , 𝑧 } ) ) ) ) ) )
118 117 adantl ( ( ( ( ( 𝐹 : ( 0 ..^ 2 ) –1-1→ dom 𝐼 ∧ ( ( 𝐼 ‘ ( 𝐹 ‘ 0 ) ) = { ( 𝑃 ‘ 0 ) , ( 𝑃 ‘ 1 ) } ∧ ( 𝐼 ‘ ( 𝐹 ‘ 1 ) ) = { ( 𝑃 ‘ 1 ) , ( 𝑃 ‘ 2 ) } ) ) ∧ 𝐺 ∈ USGraph ) ∧ 𝑃 : ( 0 ... 2 ) ⟶ 𝑉 ) ∧ 𝑥 = ( 𝑃 ‘ 0 ) ) → ( 𝑦 = ( 𝑃 ‘ 1 ) → ( 𝑧 = ( 𝑃 ‘ 2 ) → ( ( ( 𝐼 ‘ ( 𝐹 ‘ 0 ) ) = { ( 𝑃 ‘ 0 ) , ( 𝑃 ‘ 1 ) } ∧ ( 𝐼 ‘ ( 𝐹 ‘ 1 ) ) = { ( 𝑃 ‘ 1 ) , ( 𝑃 ‘ 2 ) } ) → ( ( ( 𝑃 ‘ 0 ) = 𝑥 ∧ ( 𝑃 ‘ 1 ) = 𝑦 ∧ ( 𝑃 ‘ 2 ) = 𝑧 ) ∧ ( ( 𝐼 ‘ ( 𝐹 ‘ 0 ) ) = { 𝑥 , 𝑦 } ∧ ( 𝐼 ‘ ( 𝐹 ‘ 1 ) ) = { 𝑦 , 𝑧 } ) ) ) ) ) )
119 118 imp31 ( ( ( ( ( ( ( 𝐹 : ( 0 ..^ 2 ) –1-1→ dom 𝐼 ∧ ( ( 𝐼 ‘ ( 𝐹 ‘ 0 ) ) = { ( 𝑃 ‘ 0 ) , ( 𝑃 ‘ 1 ) } ∧ ( 𝐼 ‘ ( 𝐹 ‘ 1 ) ) = { ( 𝑃 ‘ 1 ) , ( 𝑃 ‘ 2 ) } ) ) ∧ 𝐺 ∈ USGraph ) ∧ 𝑃 : ( 0 ... 2 ) ⟶ 𝑉 ) ∧ 𝑥 = ( 𝑃 ‘ 0 ) ) ∧ 𝑦 = ( 𝑃 ‘ 1 ) ) ∧ 𝑧 = ( 𝑃 ‘ 2 ) ) → ( ( ( 𝐼 ‘ ( 𝐹 ‘ 0 ) ) = { ( 𝑃 ‘ 0 ) , ( 𝑃 ‘ 1 ) } ∧ ( 𝐼 ‘ ( 𝐹 ‘ 1 ) ) = { ( 𝑃 ‘ 1 ) , ( 𝑃 ‘ 2 ) } ) → ( ( ( 𝑃 ‘ 0 ) = 𝑥 ∧ ( 𝑃 ‘ 1 ) = 𝑦 ∧ ( 𝑃 ‘ 2 ) = 𝑧 ) ∧ ( ( 𝐼 ‘ ( 𝐹 ‘ 0 ) ) = { 𝑥 , 𝑦 } ∧ ( 𝐼 ‘ ( 𝐹 ‘ 1 ) ) = { 𝑦 , 𝑧 } ) ) ) )
120 98 119 rspcimedv ( ( ( ( ( ( 𝐹 : ( 0 ..^ 2 ) –1-1→ dom 𝐼 ∧ ( ( 𝐼 ‘ ( 𝐹 ‘ 0 ) ) = { ( 𝑃 ‘ 0 ) , ( 𝑃 ‘ 1 ) } ∧ ( 𝐼 ‘ ( 𝐹 ‘ 1 ) ) = { ( 𝑃 ‘ 1 ) , ( 𝑃 ‘ 2 ) } ) ) ∧ 𝐺 ∈ USGraph ) ∧ 𝑃 : ( 0 ... 2 ) ⟶ 𝑉 ) ∧ 𝑥 = ( 𝑃 ‘ 0 ) ) ∧ 𝑦 = ( 𝑃 ‘ 1 ) ) → ( ( ( 𝐼 ‘ ( 𝐹 ‘ 0 ) ) = { ( 𝑃 ‘ 0 ) , ( 𝑃 ‘ 1 ) } ∧ ( 𝐼 ‘ ( 𝐹 ‘ 1 ) ) = { ( 𝑃 ‘ 1 ) , ( 𝑃 ‘ 2 ) } ) → ∃ 𝑧 ∈ ( 𝑉 ∖ { 𝑥 , 𝑦 } ) ( ( ( 𝑃 ‘ 0 ) = 𝑥 ∧ ( 𝑃 ‘ 1 ) = 𝑦 ∧ ( 𝑃 ‘ 2 ) = 𝑧 ) ∧ ( ( 𝐼 ‘ ( 𝐹 ‘ 0 ) ) = { 𝑥 , 𝑦 } ∧ ( 𝐼 ‘ ( 𝐹 ‘ 1 ) ) = { 𝑦 , 𝑧 } ) ) ) )
121 37 120 rspcimedv ( ( ( ( ( 𝐹 : ( 0 ..^ 2 ) –1-1→ dom 𝐼 ∧ ( ( 𝐼 ‘ ( 𝐹 ‘ 0 ) ) = { ( 𝑃 ‘ 0 ) , ( 𝑃 ‘ 1 ) } ∧ ( 𝐼 ‘ ( 𝐹 ‘ 1 ) ) = { ( 𝑃 ‘ 1 ) , ( 𝑃 ‘ 2 ) } ) ) ∧ 𝐺 ∈ USGraph ) ∧ 𝑃 : ( 0 ... 2 ) ⟶ 𝑉 ) ∧ 𝑥 = ( 𝑃 ‘ 0 ) ) → ( ( ( 𝐼 ‘ ( 𝐹 ‘ 0 ) ) = { ( 𝑃 ‘ 0 ) , ( 𝑃 ‘ 1 ) } ∧ ( 𝐼 ‘ ( 𝐹 ‘ 1 ) ) = { ( 𝑃 ‘ 1 ) , ( 𝑃 ‘ 2 ) } ) → ∃ 𝑦 ∈ ( 𝑉 ∖ { 𝑥 } ) ∃ 𝑧 ∈ ( 𝑉 ∖ { 𝑥 , 𝑦 } ) ( ( ( 𝑃 ‘ 0 ) = 𝑥 ∧ ( 𝑃 ‘ 1 ) = 𝑦 ∧ ( 𝑃 ‘ 2 ) = 𝑧 ) ∧ ( ( 𝐼 ‘ ( 𝐹 ‘ 0 ) ) = { 𝑥 , 𝑦 } ∧ ( 𝐼 ‘ ( 𝐹 ‘ 1 ) ) = { 𝑦 , 𝑧 } ) ) ) )
122 10 121 rspcimedv ( ( ( ( 𝐹 : ( 0 ..^ 2 ) –1-1→ dom 𝐼 ∧ ( ( 𝐼 ‘ ( 𝐹 ‘ 0 ) ) = { ( 𝑃 ‘ 0 ) , ( 𝑃 ‘ 1 ) } ∧ ( 𝐼 ‘ ( 𝐹 ‘ 1 ) ) = { ( 𝑃 ‘ 1 ) , ( 𝑃 ‘ 2 ) } ) ) ∧ 𝐺 ∈ USGraph ) ∧ 𝑃 : ( 0 ... 2 ) ⟶ 𝑉 ) → ( ( ( 𝐼 ‘ ( 𝐹 ‘ 0 ) ) = { ( 𝑃 ‘ 0 ) , ( 𝑃 ‘ 1 ) } ∧ ( 𝐼 ‘ ( 𝐹 ‘ 1 ) ) = { ( 𝑃 ‘ 1 ) , ( 𝑃 ‘ 2 ) } ) → ∃ 𝑥𝑉𝑦 ∈ ( 𝑉 ∖ { 𝑥 } ) ∃ 𝑧 ∈ ( 𝑉 ∖ { 𝑥 , 𝑦 } ) ( ( ( 𝑃 ‘ 0 ) = 𝑥 ∧ ( 𝑃 ‘ 1 ) = 𝑦 ∧ ( 𝑃 ‘ 2 ) = 𝑧 ) ∧ ( ( 𝐼 ‘ ( 𝐹 ‘ 0 ) ) = { 𝑥 , 𝑦 } ∧ ( 𝐼 ‘ ( 𝐹 ‘ 1 ) ) = { 𝑦 , 𝑧 } ) ) ) )
123 122 exp41 ( 𝐹 : ( 0 ..^ 2 ) –1-1→ dom 𝐼 → ( ( ( 𝐼 ‘ ( 𝐹 ‘ 0 ) ) = { ( 𝑃 ‘ 0 ) , ( 𝑃 ‘ 1 ) } ∧ ( 𝐼 ‘ ( 𝐹 ‘ 1 ) ) = { ( 𝑃 ‘ 1 ) , ( 𝑃 ‘ 2 ) } ) → ( 𝐺 ∈ USGraph → ( 𝑃 : ( 0 ... 2 ) ⟶ 𝑉 → ( ( ( 𝐼 ‘ ( 𝐹 ‘ 0 ) ) = { ( 𝑃 ‘ 0 ) , ( 𝑃 ‘ 1 ) } ∧ ( 𝐼 ‘ ( 𝐹 ‘ 1 ) ) = { ( 𝑃 ‘ 1 ) , ( 𝑃 ‘ 2 ) } ) → ∃ 𝑥𝑉𝑦 ∈ ( 𝑉 ∖ { 𝑥 } ) ∃ 𝑧 ∈ ( 𝑉 ∖ { 𝑥 , 𝑦 } ) ( ( ( 𝑃 ‘ 0 ) = 𝑥 ∧ ( 𝑃 ‘ 1 ) = 𝑦 ∧ ( 𝑃 ‘ 2 ) = 𝑧 ) ∧ ( ( 𝐼 ‘ ( 𝐹 ‘ 0 ) ) = { 𝑥 , 𝑦 } ∧ ( 𝐼 ‘ ( 𝐹 ‘ 1 ) ) = { 𝑦 , 𝑧 } ) ) ) ) ) ) )
124 123 com15 ( ( ( 𝐼 ‘ ( 𝐹 ‘ 0 ) ) = { ( 𝑃 ‘ 0 ) , ( 𝑃 ‘ 1 ) } ∧ ( 𝐼 ‘ ( 𝐹 ‘ 1 ) ) = { ( 𝑃 ‘ 1 ) , ( 𝑃 ‘ 2 ) } ) → ( ( ( 𝐼 ‘ ( 𝐹 ‘ 0 ) ) = { ( 𝑃 ‘ 0 ) , ( 𝑃 ‘ 1 ) } ∧ ( 𝐼 ‘ ( 𝐹 ‘ 1 ) ) = { ( 𝑃 ‘ 1 ) , ( 𝑃 ‘ 2 ) } ) → ( 𝐺 ∈ USGraph → ( 𝑃 : ( 0 ... 2 ) ⟶ 𝑉 → ( 𝐹 : ( 0 ..^ 2 ) –1-1→ dom 𝐼 → ∃ 𝑥𝑉𝑦 ∈ ( 𝑉 ∖ { 𝑥 } ) ∃ 𝑧 ∈ ( 𝑉 ∖ { 𝑥 , 𝑦 } ) ( ( ( 𝑃 ‘ 0 ) = 𝑥 ∧ ( 𝑃 ‘ 1 ) = 𝑦 ∧ ( 𝑃 ‘ 2 ) = 𝑧 ) ∧ ( ( 𝐼 ‘ ( 𝐹 ‘ 0 ) ) = { 𝑥 , 𝑦 } ∧ ( 𝐼 ‘ ( 𝐹 ‘ 1 ) ) = { 𝑦 , 𝑧 } ) ) ) ) ) ) )
125 124 pm2.43i ( ( ( 𝐼 ‘ ( 𝐹 ‘ 0 ) ) = { ( 𝑃 ‘ 0 ) , ( 𝑃 ‘ 1 ) } ∧ ( 𝐼 ‘ ( 𝐹 ‘ 1 ) ) = { ( 𝑃 ‘ 1 ) , ( 𝑃 ‘ 2 ) } ) → ( 𝐺 ∈ USGraph → ( 𝑃 : ( 0 ... 2 ) ⟶ 𝑉 → ( 𝐹 : ( 0 ..^ 2 ) –1-1→ dom 𝐼 → ∃ 𝑥𝑉𝑦 ∈ ( 𝑉 ∖ { 𝑥 } ) ∃ 𝑧 ∈ ( 𝑉 ∖ { 𝑥 , 𝑦 } ) ( ( ( 𝑃 ‘ 0 ) = 𝑥 ∧ ( 𝑃 ‘ 1 ) = 𝑦 ∧ ( 𝑃 ‘ 2 ) = 𝑧 ) ∧ ( ( 𝐼 ‘ ( 𝐹 ‘ 0 ) ) = { 𝑥 , 𝑦 } ∧ ( 𝐼 ‘ ( 𝐹 ‘ 1 ) ) = { 𝑦 , 𝑧 } ) ) ) ) ) )
126 125 com12 ( 𝐺 ∈ USGraph → ( ( ( 𝐼 ‘ ( 𝐹 ‘ 0 ) ) = { ( 𝑃 ‘ 0 ) , ( 𝑃 ‘ 1 ) } ∧ ( 𝐼 ‘ ( 𝐹 ‘ 1 ) ) = { ( 𝑃 ‘ 1 ) , ( 𝑃 ‘ 2 ) } ) → ( 𝑃 : ( 0 ... 2 ) ⟶ 𝑉 → ( 𝐹 : ( 0 ..^ 2 ) –1-1→ dom 𝐼 → ∃ 𝑥𝑉𝑦 ∈ ( 𝑉 ∖ { 𝑥 } ) ∃ 𝑧 ∈ ( 𝑉 ∖ { 𝑥 , 𝑦 } ) ( ( ( 𝑃 ‘ 0 ) = 𝑥 ∧ ( 𝑃 ‘ 1 ) = 𝑦 ∧ ( 𝑃 ‘ 2 ) = 𝑧 ) ∧ ( ( 𝐼 ‘ ( 𝐹 ‘ 0 ) ) = { 𝑥 , 𝑦 } ∧ ( 𝐼 ‘ ( 𝐹 ‘ 1 ) ) = { 𝑦 , 𝑧 } ) ) ) ) ) )
127 126 adantr ( ( 𝐺 ∈ USGraph ∧ ( ♯ ‘ 𝐹 ) = 2 ) → ( ( ( 𝐼 ‘ ( 𝐹 ‘ 0 ) ) = { ( 𝑃 ‘ 0 ) , ( 𝑃 ‘ 1 ) } ∧ ( 𝐼 ‘ ( 𝐹 ‘ 1 ) ) = { ( 𝑃 ‘ 1 ) , ( 𝑃 ‘ 2 ) } ) → ( 𝑃 : ( 0 ... 2 ) ⟶ 𝑉 → ( 𝐹 : ( 0 ..^ 2 ) –1-1→ dom 𝐼 → ∃ 𝑥𝑉𝑦 ∈ ( 𝑉 ∖ { 𝑥 } ) ∃ 𝑧 ∈ ( 𝑉 ∖ { 𝑥 , 𝑦 } ) ( ( ( 𝑃 ‘ 0 ) = 𝑥 ∧ ( 𝑃 ‘ 1 ) = 𝑦 ∧ ( 𝑃 ‘ 2 ) = 𝑧 ) ∧ ( ( 𝐼 ‘ ( 𝐹 ‘ 0 ) ) = { 𝑥 , 𝑦 } ∧ ( 𝐼 ‘ ( 𝐹 ‘ 1 ) ) = { 𝑦 , 𝑧 } ) ) ) ) ) )
128 oveq2 ( ( ♯ ‘ 𝐹 ) = 2 → ( 0 ..^ ( ♯ ‘ 𝐹 ) ) = ( 0 ..^ 2 ) )
129 128 raleqdv ( ( ♯ ‘ 𝐹 ) = 2 → ( ∀ 𝑖 ∈ ( 0 ..^ ( ♯ ‘ 𝐹 ) ) ( 𝐼 ‘ ( 𝐹𝑖 ) ) = { ( 𝑃𝑖 ) , ( 𝑃 ‘ ( 𝑖 + 1 ) ) } ↔ ∀ 𝑖 ∈ ( 0 ..^ 2 ) ( 𝐼 ‘ ( 𝐹𝑖 ) ) = { ( 𝑃𝑖 ) , ( 𝑃 ‘ ( 𝑖 + 1 ) ) } ) )
130 fzo0to2pr ( 0 ..^ 2 ) = { 0 , 1 }
131 130 raleqi ( ∀ 𝑖 ∈ ( 0 ..^ 2 ) ( 𝐼 ‘ ( 𝐹𝑖 ) ) = { ( 𝑃𝑖 ) , ( 𝑃 ‘ ( 𝑖 + 1 ) ) } ↔ ∀ 𝑖 ∈ { 0 , 1 } ( 𝐼 ‘ ( 𝐹𝑖 ) ) = { ( 𝑃𝑖 ) , ( 𝑃 ‘ ( 𝑖 + 1 ) ) } )
132 2wlklem ( ∀ 𝑖 ∈ { 0 , 1 } ( 𝐼 ‘ ( 𝐹𝑖 ) ) = { ( 𝑃𝑖 ) , ( 𝑃 ‘ ( 𝑖 + 1 ) ) } ↔ ( ( 𝐼 ‘ ( 𝐹 ‘ 0 ) ) = { ( 𝑃 ‘ 0 ) , ( 𝑃 ‘ 1 ) } ∧ ( 𝐼 ‘ ( 𝐹 ‘ 1 ) ) = { ( 𝑃 ‘ 1 ) , ( 𝑃 ‘ 2 ) } ) )
133 131 132 bitri ( ∀ 𝑖 ∈ ( 0 ..^ 2 ) ( 𝐼 ‘ ( 𝐹𝑖 ) ) = { ( 𝑃𝑖 ) , ( 𝑃 ‘ ( 𝑖 + 1 ) ) } ↔ ( ( 𝐼 ‘ ( 𝐹 ‘ 0 ) ) = { ( 𝑃 ‘ 0 ) , ( 𝑃 ‘ 1 ) } ∧ ( 𝐼 ‘ ( 𝐹 ‘ 1 ) ) = { ( 𝑃 ‘ 1 ) , ( 𝑃 ‘ 2 ) } ) )
134 129 133 bitrdi ( ( ♯ ‘ 𝐹 ) = 2 → ( ∀ 𝑖 ∈ ( 0 ..^ ( ♯ ‘ 𝐹 ) ) ( 𝐼 ‘ ( 𝐹𝑖 ) ) = { ( 𝑃𝑖 ) , ( 𝑃 ‘ ( 𝑖 + 1 ) ) } ↔ ( ( 𝐼 ‘ ( 𝐹 ‘ 0 ) ) = { ( 𝑃 ‘ 0 ) , ( 𝑃 ‘ 1 ) } ∧ ( 𝐼 ‘ ( 𝐹 ‘ 1 ) ) = { ( 𝑃 ‘ 1 ) , ( 𝑃 ‘ 2 ) } ) ) )
135 134 adantl ( ( 𝐺 ∈ USGraph ∧ ( ♯ ‘ 𝐹 ) = 2 ) → ( ∀ 𝑖 ∈ ( 0 ..^ ( ♯ ‘ 𝐹 ) ) ( 𝐼 ‘ ( 𝐹𝑖 ) ) = { ( 𝑃𝑖 ) , ( 𝑃 ‘ ( 𝑖 + 1 ) ) } ↔ ( ( 𝐼 ‘ ( 𝐹 ‘ 0 ) ) = { ( 𝑃 ‘ 0 ) , ( 𝑃 ‘ 1 ) } ∧ ( 𝐼 ‘ ( 𝐹 ‘ 1 ) ) = { ( 𝑃 ‘ 1 ) , ( 𝑃 ‘ 2 ) } ) ) )
136 oveq2 ( ( ♯ ‘ 𝐹 ) = 2 → ( 0 ... ( ♯ ‘ 𝐹 ) ) = ( 0 ... 2 ) )
137 136 feq2d ( ( ♯ ‘ 𝐹 ) = 2 → ( 𝑃 : ( 0 ... ( ♯ ‘ 𝐹 ) ) ⟶ 𝑉𝑃 : ( 0 ... 2 ) ⟶ 𝑉 ) )
138 137 adantl ( ( 𝐺 ∈ USGraph ∧ ( ♯ ‘ 𝐹 ) = 2 ) → ( 𝑃 : ( 0 ... ( ♯ ‘ 𝐹 ) ) ⟶ 𝑉𝑃 : ( 0 ... 2 ) ⟶ 𝑉 ) )
139 f1eq2 ( ( 0 ..^ ( ♯ ‘ 𝐹 ) ) = ( 0 ..^ 2 ) → ( 𝐹 : ( 0 ..^ ( ♯ ‘ 𝐹 ) ) –1-1→ dom 𝐼𝐹 : ( 0 ..^ 2 ) –1-1→ dom 𝐼 ) )
140 128 139 syl ( ( ♯ ‘ 𝐹 ) = 2 → ( 𝐹 : ( 0 ..^ ( ♯ ‘ 𝐹 ) ) –1-1→ dom 𝐼𝐹 : ( 0 ..^ 2 ) –1-1→ dom 𝐼 ) )
141 140 imbi1d ( ( ♯ ‘ 𝐹 ) = 2 → ( ( 𝐹 : ( 0 ..^ ( ♯ ‘ 𝐹 ) ) –1-1→ dom 𝐼 → ∃ 𝑥𝑉𝑦 ∈ ( 𝑉 ∖ { 𝑥 } ) ∃ 𝑧 ∈ ( 𝑉 ∖ { 𝑥 , 𝑦 } ) ( ( ( 𝑃 ‘ 0 ) = 𝑥 ∧ ( 𝑃 ‘ 1 ) = 𝑦 ∧ ( 𝑃 ‘ 2 ) = 𝑧 ) ∧ ( ( 𝐼 ‘ ( 𝐹 ‘ 0 ) ) = { 𝑥 , 𝑦 } ∧ ( 𝐼 ‘ ( 𝐹 ‘ 1 ) ) = { 𝑦 , 𝑧 } ) ) ) ↔ ( 𝐹 : ( 0 ..^ 2 ) –1-1→ dom 𝐼 → ∃ 𝑥𝑉𝑦 ∈ ( 𝑉 ∖ { 𝑥 } ) ∃ 𝑧 ∈ ( 𝑉 ∖ { 𝑥 , 𝑦 } ) ( ( ( 𝑃 ‘ 0 ) = 𝑥 ∧ ( 𝑃 ‘ 1 ) = 𝑦 ∧ ( 𝑃 ‘ 2 ) = 𝑧 ) ∧ ( ( 𝐼 ‘ ( 𝐹 ‘ 0 ) ) = { 𝑥 , 𝑦 } ∧ ( 𝐼 ‘ ( 𝐹 ‘ 1 ) ) = { 𝑦 , 𝑧 } ) ) ) ) )
142 141 adantl ( ( 𝐺 ∈ USGraph ∧ ( ♯ ‘ 𝐹 ) = 2 ) → ( ( 𝐹 : ( 0 ..^ ( ♯ ‘ 𝐹 ) ) –1-1→ dom 𝐼 → ∃ 𝑥𝑉𝑦 ∈ ( 𝑉 ∖ { 𝑥 } ) ∃ 𝑧 ∈ ( 𝑉 ∖ { 𝑥 , 𝑦 } ) ( ( ( 𝑃 ‘ 0 ) = 𝑥 ∧ ( 𝑃 ‘ 1 ) = 𝑦 ∧ ( 𝑃 ‘ 2 ) = 𝑧 ) ∧ ( ( 𝐼 ‘ ( 𝐹 ‘ 0 ) ) = { 𝑥 , 𝑦 } ∧ ( 𝐼 ‘ ( 𝐹 ‘ 1 ) ) = { 𝑦 , 𝑧 } ) ) ) ↔ ( 𝐹 : ( 0 ..^ 2 ) –1-1→ dom 𝐼 → ∃ 𝑥𝑉𝑦 ∈ ( 𝑉 ∖ { 𝑥 } ) ∃ 𝑧 ∈ ( 𝑉 ∖ { 𝑥 , 𝑦 } ) ( ( ( 𝑃 ‘ 0 ) = 𝑥 ∧ ( 𝑃 ‘ 1 ) = 𝑦 ∧ ( 𝑃 ‘ 2 ) = 𝑧 ) ∧ ( ( 𝐼 ‘ ( 𝐹 ‘ 0 ) ) = { 𝑥 , 𝑦 } ∧ ( 𝐼 ‘ ( 𝐹 ‘ 1 ) ) = { 𝑦 , 𝑧 } ) ) ) ) )
143 138 142 imbi12d ( ( 𝐺 ∈ USGraph ∧ ( ♯ ‘ 𝐹 ) = 2 ) → ( ( 𝑃 : ( 0 ... ( ♯ ‘ 𝐹 ) ) ⟶ 𝑉 → ( 𝐹 : ( 0 ..^ ( ♯ ‘ 𝐹 ) ) –1-1→ dom 𝐼 → ∃ 𝑥𝑉𝑦 ∈ ( 𝑉 ∖ { 𝑥 } ) ∃ 𝑧 ∈ ( 𝑉 ∖ { 𝑥 , 𝑦 } ) ( ( ( 𝑃 ‘ 0 ) = 𝑥 ∧ ( 𝑃 ‘ 1 ) = 𝑦 ∧ ( 𝑃 ‘ 2 ) = 𝑧 ) ∧ ( ( 𝐼 ‘ ( 𝐹 ‘ 0 ) ) = { 𝑥 , 𝑦 } ∧ ( 𝐼 ‘ ( 𝐹 ‘ 1 ) ) = { 𝑦 , 𝑧 } ) ) ) ) ↔ ( 𝑃 : ( 0 ... 2 ) ⟶ 𝑉 → ( 𝐹 : ( 0 ..^ 2 ) –1-1→ dom 𝐼 → ∃ 𝑥𝑉𝑦 ∈ ( 𝑉 ∖ { 𝑥 } ) ∃ 𝑧 ∈ ( 𝑉 ∖ { 𝑥 , 𝑦 } ) ( ( ( 𝑃 ‘ 0 ) = 𝑥 ∧ ( 𝑃 ‘ 1 ) = 𝑦 ∧ ( 𝑃 ‘ 2 ) = 𝑧 ) ∧ ( ( 𝐼 ‘ ( 𝐹 ‘ 0 ) ) = { 𝑥 , 𝑦 } ∧ ( 𝐼 ‘ ( 𝐹 ‘ 1 ) ) = { 𝑦 , 𝑧 } ) ) ) ) ) )
144 127 135 143 3imtr4d ( ( 𝐺 ∈ USGraph ∧ ( ♯ ‘ 𝐹 ) = 2 ) → ( ∀ 𝑖 ∈ ( 0 ..^ ( ♯ ‘ 𝐹 ) ) ( 𝐼 ‘ ( 𝐹𝑖 ) ) = { ( 𝑃𝑖 ) , ( 𝑃 ‘ ( 𝑖 + 1 ) ) } → ( 𝑃 : ( 0 ... ( ♯ ‘ 𝐹 ) ) ⟶ 𝑉 → ( 𝐹 : ( 0 ..^ ( ♯ ‘ 𝐹 ) ) –1-1→ dom 𝐼 → ∃ 𝑥𝑉𝑦 ∈ ( 𝑉 ∖ { 𝑥 } ) ∃ 𝑧 ∈ ( 𝑉 ∖ { 𝑥 , 𝑦 } ) ( ( ( 𝑃 ‘ 0 ) = 𝑥 ∧ ( 𝑃 ‘ 1 ) = 𝑦 ∧ ( 𝑃 ‘ 2 ) = 𝑧 ) ∧ ( ( 𝐼 ‘ ( 𝐹 ‘ 0 ) ) = { 𝑥 , 𝑦 } ∧ ( 𝐼 ‘ ( 𝐹 ‘ 1 ) ) = { 𝑦 , 𝑧 } ) ) ) ) ) )
145 144 com14 ( 𝐹 : ( 0 ..^ ( ♯ ‘ 𝐹 ) ) –1-1→ dom 𝐼 → ( ∀ 𝑖 ∈ ( 0 ..^ ( ♯ ‘ 𝐹 ) ) ( 𝐼 ‘ ( 𝐹𝑖 ) ) = { ( 𝑃𝑖 ) , ( 𝑃 ‘ ( 𝑖 + 1 ) ) } → ( 𝑃 : ( 0 ... ( ♯ ‘ 𝐹 ) ) ⟶ 𝑉 → ( ( 𝐺 ∈ USGraph ∧ ( ♯ ‘ 𝐹 ) = 2 ) → ∃ 𝑥𝑉𝑦 ∈ ( 𝑉 ∖ { 𝑥 } ) ∃ 𝑧 ∈ ( 𝑉 ∖ { 𝑥 , 𝑦 } ) ( ( ( 𝑃 ‘ 0 ) = 𝑥 ∧ ( 𝑃 ‘ 1 ) = 𝑦 ∧ ( 𝑃 ‘ 2 ) = 𝑧 ) ∧ ( ( 𝐼 ‘ ( 𝐹 ‘ 0 ) ) = { 𝑥 , 𝑦 } ∧ ( 𝐼 ‘ ( 𝐹 ‘ 1 ) ) = { 𝑦 , 𝑧 } ) ) ) ) ) )
146 145 com23 ( 𝐹 : ( 0 ..^ ( ♯ ‘ 𝐹 ) ) –1-1→ dom 𝐼 → ( 𝑃 : ( 0 ... ( ♯ ‘ 𝐹 ) ) ⟶ 𝑉 → ( ∀ 𝑖 ∈ ( 0 ..^ ( ♯ ‘ 𝐹 ) ) ( 𝐼 ‘ ( 𝐹𝑖 ) ) = { ( 𝑃𝑖 ) , ( 𝑃 ‘ ( 𝑖 + 1 ) ) } → ( ( 𝐺 ∈ USGraph ∧ ( ♯ ‘ 𝐹 ) = 2 ) → ∃ 𝑥𝑉𝑦 ∈ ( 𝑉 ∖ { 𝑥 } ) ∃ 𝑧 ∈ ( 𝑉 ∖ { 𝑥 , 𝑦 } ) ( ( ( 𝑃 ‘ 0 ) = 𝑥 ∧ ( 𝑃 ‘ 1 ) = 𝑦 ∧ ( 𝑃 ‘ 2 ) = 𝑧 ) ∧ ( ( 𝐼 ‘ ( 𝐹 ‘ 0 ) ) = { 𝑥 , 𝑦 } ∧ ( 𝐼 ‘ ( 𝐹 ‘ 1 ) ) = { 𝑦 , 𝑧 } ) ) ) ) ) )
147 146 3imp ( ( 𝐹 : ( 0 ..^ ( ♯ ‘ 𝐹 ) ) –1-1→ dom 𝐼𝑃 : ( 0 ... ( ♯ ‘ 𝐹 ) ) ⟶ 𝑉 ∧ ∀ 𝑖 ∈ ( 0 ..^ ( ♯ ‘ 𝐹 ) ) ( 𝐼 ‘ ( 𝐹𝑖 ) ) = { ( 𝑃𝑖 ) , ( 𝑃 ‘ ( 𝑖 + 1 ) ) } ) → ( ( 𝐺 ∈ USGraph ∧ ( ♯ ‘ 𝐹 ) = 2 ) → ∃ 𝑥𝑉𝑦 ∈ ( 𝑉 ∖ { 𝑥 } ) ∃ 𝑧 ∈ ( 𝑉 ∖ { 𝑥 , 𝑦 } ) ( ( ( 𝑃 ‘ 0 ) = 𝑥 ∧ ( 𝑃 ‘ 1 ) = 𝑦 ∧ ( 𝑃 ‘ 2 ) = 𝑧 ) ∧ ( ( 𝐼 ‘ ( 𝐹 ‘ 0 ) ) = { 𝑥 , 𝑦 } ∧ ( 𝐼 ‘ ( 𝐹 ‘ 1 ) ) = { 𝑦 , 𝑧 } ) ) ) )