Metamath Proof Explorer


Theorem permac8prim

Description: The Axiom of Choice ac8prim holds in permutation models. Part of Exercise II.9.3 of Kunen2 p. 149. Note that ax-ac requires Regularity for its derivation from the usual Axiom of Choice and does not necessarily hold in permutation models. (Contributed by Eric Schmidt, 16-Nov-2025)

Ref Expression
Hypotheses permmodel.1 𝐹 : V –1-1-onto→ V
permmodel.2 𝑅 = ( 𝐹 ∘ E )
Assertion permac8prim ( ( ∀ 𝑧 ( 𝑧 𝑅 𝑥 → ∃ 𝑤 𝑤 𝑅 𝑧 ) ∧ ∀ 𝑧𝑤 ( ( 𝑧 𝑅 𝑥𝑤 𝑅 𝑥 ) → ( ¬ 𝑧 = 𝑤 → ∀ 𝑦 ( 𝑦 𝑅 𝑧 → ¬ 𝑦 𝑅 𝑤 ) ) ) ) → ∃ 𝑦𝑧 ( 𝑧 𝑅 𝑥 → ∃ 𝑤𝑣 ( ( 𝑣 𝑅 𝑧𝑣 𝑅 𝑦 ) ↔ 𝑣 = 𝑤 ) ) )

Proof

Step Hyp Ref Expression
1 permmodel.1 𝐹 : V –1-1-onto→ V
2 permmodel.2 𝑅 = ( 𝐹 ∘ E )
3 df-ral ( ∀ 𝑧 ∈ ( 𝐹𝑥 ) ( 𝐹𝑧 ) ≠ ∅ ↔ ∀ 𝑧 ( 𝑧 ∈ ( 𝐹𝑥 ) → ( 𝐹𝑧 ) ≠ ∅ ) )
4 f1ofn ( 𝐹 : V –1-1-onto→ V → 𝐹 Fn V )
5 1 4 ax-mp 𝐹 Fn V
6 ssv ( 𝐹𝑥 ) ⊆ V
7 neeq1 ( 𝑡 = ( 𝐹𝑧 ) → ( 𝑡 ≠ ∅ ↔ ( 𝐹𝑧 ) ≠ ∅ ) )
8 7 ralima ( ( 𝐹 Fn V ∧ ( 𝐹𝑥 ) ⊆ V ) → ( ∀ 𝑡 ∈ ( 𝐹 “ ( 𝐹𝑥 ) ) 𝑡 ≠ ∅ ↔ ∀ 𝑧 ∈ ( 𝐹𝑥 ) ( 𝐹𝑧 ) ≠ ∅ ) )
9 5 6 8 mp2an ( ∀ 𝑡 ∈ ( 𝐹 “ ( 𝐹𝑥 ) ) 𝑡 ≠ ∅ ↔ ∀ 𝑧 ∈ ( 𝐹𝑥 ) ( 𝐹𝑧 ) ≠ ∅ )
10 vex 𝑧 ∈ V
11 vex 𝑥 ∈ V
12 1 2 10 11 brpermmodel ( 𝑧 𝑅 𝑥𝑧 ∈ ( 𝐹𝑥 ) )
13 vex 𝑤 ∈ V
14 1 2 13 10 brpermmodel ( 𝑤 𝑅 𝑧𝑤 ∈ ( 𝐹𝑧 ) )
15 14 exbii ( ∃ 𝑤 𝑤 𝑅 𝑧 ↔ ∃ 𝑤 𝑤 ∈ ( 𝐹𝑧 ) )
16 n0 ( ( 𝐹𝑧 ) ≠ ∅ ↔ ∃ 𝑤 𝑤 ∈ ( 𝐹𝑧 ) )
17 15 16 bitr4i ( ∃ 𝑤 𝑤 𝑅 𝑧 ↔ ( 𝐹𝑧 ) ≠ ∅ )
18 12 17 imbi12i ( ( 𝑧 𝑅 𝑥 → ∃ 𝑤 𝑤 𝑅 𝑧 ) ↔ ( 𝑧 ∈ ( 𝐹𝑥 ) → ( 𝐹𝑧 ) ≠ ∅ ) )
19 18 albii ( ∀ 𝑧 ( 𝑧 𝑅 𝑥 → ∃ 𝑤 𝑤 𝑅 𝑧 ) ↔ ∀ 𝑧 ( 𝑧 ∈ ( 𝐹𝑥 ) → ( 𝐹𝑧 ) ≠ ∅ ) )
20 3 9 19 3bitr4i ( ∀ 𝑡 ∈ ( 𝐹 “ ( 𝐹𝑥 ) ) 𝑡 ≠ ∅ ↔ ∀ 𝑧 ( 𝑧 𝑅 𝑥 → ∃ 𝑤 𝑤 𝑅 𝑧 ) )
21 neeq2 ( 𝑞 = ( 𝐹𝑤 ) → ( 𝑡𝑞𝑡 ≠ ( 𝐹𝑤 ) ) )
22 ineq2 ( 𝑞 = ( 𝐹𝑤 ) → ( 𝑡𝑞 ) = ( 𝑡 ∩ ( 𝐹𝑤 ) ) )
23 22 eqeq1d ( 𝑞 = ( 𝐹𝑤 ) → ( ( 𝑡𝑞 ) = ∅ ↔ ( 𝑡 ∩ ( 𝐹𝑤 ) ) = ∅ ) )
24 21 23 imbi12d ( 𝑞 = ( 𝐹𝑤 ) → ( ( 𝑡𝑞 → ( 𝑡𝑞 ) = ∅ ) ↔ ( 𝑡 ≠ ( 𝐹𝑤 ) → ( 𝑡 ∩ ( 𝐹𝑤 ) ) = ∅ ) ) )
25 24 ralima ( ( 𝐹 Fn V ∧ ( 𝐹𝑥 ) ⊆ V ) → ( ∀ 𝑞 ∈ ( 𝐹 “ ( 𝐹𝑥 ) ) ( 𝑡𝑞 → ( 𝑡𝑞 ) = ∅ ) ↔ ∀ 𝑤 ∈ ( 𝐹𝑥 ) ( 𝑡 ≠ ( 𝐹𝑤 ) → ( 𝑡 ∩ ( 𝐹𝑤 ) ) = ∅ ) ) )
26 5 6 25 mp2an ( ∀ 𝑞 ∈ ( 𝐹 “ ( 𝐹𝑥 ) ) ( 𝑡𝑞 → ( 𝑡𝑞 ) = ∅ ) ↔ ∀ 𝑤 ∈ ( 𝐹𝑥 ) ( 𝑡 ≠ ( 𝐹𝑤 ) → ( 𝑡 ∩ ( 𝐹𝑤 ) ) = ∅ ) )
27 26 ralbii ( ∀ 𝑡 ∈ ( 𝐹 “ ( 𝐹𝑥 ) ) ∀ 𝑞 ∈ ( 𝐹 “ ( 𝐹𝑥 ) ) ( 𝑡𝑞 → ( 𝑡𝑞 ) = ∅ ) ↔ ∀ 𝑡 ∈ ( 𝐹 “ ( 𝐹𝑥 ) ) ∀ 𝑤 ∈ ( 𝐹𝑥 ) ( 𝑡 ≠ ( 𝐹𝑤 ) → ( 𝑡 ∩ ( 𝐹𝑤 ) ) = ∅ ) )
28 neeq1 ( 𝑡 = ( 𝐹𝑧 ) → ( 𝑡 ≠ ( 𝐹𝑤 ) ↔ ( 𝐹𝑧 ) ≠ ( 𝐹𝑤 ) ) )
29 ineq1 ( 𝑡 = ( 𝐹𝑧 ) → ( 𝑡 ∩ ( 𝐹𝑤 ) ) = ( ( 𝐹𝑧 ) ∩ ( 𝐹𝑤 ) ) )
30 29 eqeq1d ( 𝑡 = ( 𝐹𝑧 ) → ( ( 𝑡 ∩ ( 𝐹𝑤 ) ) = ∅ ↔ ( ( 𝐹𝑧 ) ∩ ( 𝐹𝑤 ) ) = ∅ ) )
31 28 30 imbi12d ( 𝑡 = ( 𝐹𝑧 ) → ( ( 𝑡 ≠ ( 𝐹𝑤 ) → ( 𝑡 ∩ ( 𝐹𝑤 ) ) = ∅ ) ↔ ( ( 𝐹𝑧 ) ≠ ( 𝐹𝑤 ) → ( ( 𝐹𝑧 ) ∩ ( 𝐹𝑤 ) ) = ∅ ) ) )
32 31 ralbidv ( 𝑡 = ( 𝐹𝑧 ) → ( ∀ 𝑤 ∈ ( 𝐹𝑥 ) ( 𝑡 ≠ ( 𝐹𝑤 ) → ( 𝑡 ∩ ( 𝐹𝑤 ) ) = ∅ ) ↔ ∀ 𝑤 ∈ ( 𝐹𝑥 ) ( ( 𝐹𝑧 ) ≠ ( 𝐹𝑤 ) → ( ( 𝐹𝑧 ) ∩ ( 𝐹𝑤 ) ) = ∅ ) ) )
33 32 ralima ( ( 𝐹 Fn V ∧ ( 𝐹𝑥 ) ⊆ V ) → ( ∀ 𝑡 ∈ ( 𝐹 “ ( 𝐹𝑥 ) ) ∀ 𝑤 ∈ ( 𝐹𝑥 ) ( 𝑡 ≠ ( 𝐹𝑤 ) → ( 𝑡 ∩ ( 𝐹𝑤 ) ) = ∅ ) ↔ ∀ 𝑧 ∈ ( 𝐹𝑥 ) ∀ 𝑤 ∈ ( 𝐹𝑥 ) ( ( 𝐹𝑧 ) ≠ ( 𝐹𝑤 ) → ( ( 𝐹𝑧 ) ∩ ( 𝐹𝑤 ) ) = ∅ ) ) )
34 5 6 33 mp2an ( ∀ 𝑡 ∈ ( 𝐹 “ ( 𝐹𝑥 ) ) ∀ 𝑤 ∈ ( 𝐹𝑥 ) ( 𝑡 ≠ ( 𝐹𝑤 ) → ( 𝑡 ∩ ( 𝐹𝑤 ) ) = ∅ ) ↔ ∀ 𝑧 ∈ ( 𝐹𝑥 ) ∀ 𝑤 ∈ ( 𝐹𝑥 ) ( ( 𝐹𝑧 ) ≠ ( 𝐹𝑤 ) → ( ( 𝐹𝑧 ) ∩ ( 𝐹𝑤 ) ) = ∅ ) )
35 r2al ( ∀ 𝑧 ∈ ( 𝐹𝑥 ) ∀ 𝑤 ∈ ( 𝐹𝑥 ) ( ( 𝐹𝑧 ) ≠ ( 𝐹𝑤 ) → ( ( 𝐹𝑧 ) ∩ ( 𝐹𝑤 ) ) = ∅ ) ↔ ∀ 𝑧𝑤 ( ( 𝑧 ∈ ( 𝐹𝑥 ) ∧ 𝑤 ∈ ( 𝐹𝑥 ) ) → ( ( 𝐹𝑧 ) ≠ ( 𝐹𝑤 ) → ( ( 𝐹𝑧 ) ∩ ( 𝐹𝑤 ) ) = ∅ ) ) )
36 27 34 35 3bitri ( ∀ 𝑡 ∈ ( 𝐹 “ ( 𝐹𝑥 ) ) ∀ 𝑞 ∈ ( 𝐹 “ ( 𝐹𝑥 ) ) ( 𝑡𝑞 → ( 𝑡𝑞 ) = ∅ ) ↔ ∀ 𝑧𝑤 ( ( 𝑧 ∈ ( 𝐹𝑥 ) ∧ 𝑤 ∈ ( 𝐹𝑥 ) ) → ( ( 𝐹𝑧 ) ≠ ( 𝐹𝑤 ) → ( ( 𝐹𝑧 ) ∩ ( 𝐹𝑤 ) ) = ∅ ) ) )
37 1 2 13 11 brpermmodel ( 𝑤 𝑅 𝑥𝑤 ∈ ( 𝐹𝑥 ) )
38 12 37 anbi12i ( ( 𝑧 𝑅 𝑥𝑤 𝑅 𝑥 ) ↔ ( 𝑧 ∈ ( 𝐹𝑥 ) ∧ 𝑤 ∈ ( 𝐹𝑥 ) ) )
39 df-ne ( ( 𝐹𝑧 ) ≠ ( 𝐹𝑤 ) ↔ ¬ ( 𝐹𝑧 ) = ( 𝐹𝑤 ) )
40 f1of1 ( 𝐹 : V –1-1-onto→ V → 𝐹 : V –1-1→ V )
41 1 40 ax-mp 𝐹 : V –1-1→ V
42 f1fveq ( ( 𝐹 : V –1-1→ V ∧ ( 𝑧 ∈ V ∧ 𝑤 ∈ V ) ) → ( ( 𝐹𝑧 ) = ( 𝐹𝑤 ) ↔ 𝑧 = 𝑤 ) )
43 41 42 mpan ( ( 𝑧 ∈ V ∧ 𝑤 ∈ V ) → ( ( 𝐹𝑧 ) = ( 𝐹𝑤 ) ↔ 𝑧 = 𝑤 ) )
44 43 el2v ( ( 𝐹𝑧 ) = ( 𝐹𝑤 ) ↔ 𝑧 = 𝑤 )
45 44 notbii ( ¬ ( 𝐹𝑧 ) = ( 𝐹𝑤 ) ↔ ¬ 𝑧 = 𝑤 )
46 39 45 bitr2i ( ¬ 𝑧 = 𝑤 ↔ ( 𝐹𝑧 ) ≠ ( 𝐹𝑤 ) )
47 vex 𝑦 ∈ V
48 1 2 47 10 brpermmodel ( 𝑦 𝑅 𝑧𝑦 ∈ ( 𝐹𝑧 ) )
49 1 2 47 13 brpermmodel ( 𝑦 𝑅 𝑤𝑦 ∈ ( 𝐹𝑤 ) )
50 49 notbii ( ¬ 𝑦 𝑅 𝑤 ↔ ¬ 𝑦 ∈ ( 𝐹𝑤 ) )
51 48 50 imbi12i ( ( 𝑦 𝑅 𝑧 → ¬ 𝑦 𝑅 𝑤 ) ↔ ( 𝑦 ∈ ( 𝐹𝑧 ) → ¬ 𝑦 ∈ ( 𝐹𝑤 ) ) )
52 51 albii ( ∀ 𝑦 ( 𝑦 𝑅 𝑧 → ¬ 𝑦 𝑅 𝑤 ) ↔ ∀ 𝑦 ( 𝑦 ∈ ( 𝐹𝑧 ) → ¬ 𝑦 ∈ ( 𝐹𝑤 ) ) )
53 disj1 ( ( ( 𝐹𝑧 ) ∩ ( 𝐹𝑤 ) ) = ∅ ↔ ∀ 𝑦 ( 𝑦 ∈ ( 𝐹𝑧 ) → ¬ 𝑦 ∈ ( 𝐹𝑤 ) ) )
54 52 53 bitr4i ( ∀ 𝑦 ( 𝑦 𝑅 𝑧 → ¬ 𝑦 𝑅 𝑤 ) ↔ ( ( 𝐹𝑧 ) ∩ ( 𝐹𝑤 ) ) = ∅ )
55 46 54 imbi12i ( ( ¬ 𝑧 = 𝑤 → ∀ 𝑦 ( 𝑦 𝑅 𝑧 → ¬ 𝑦 𝑅 𝑤 ) ) ↔ ( ( 𝐹𝑧 ) ≠ ( 𝐹𝑤 ) → ( ( 𝐹𝑧 ) ∩ ( 𝐹𝑤 ) ) = ∅ ) )
56 38 55 imbi12i ( ( ( 𝑧 𝑅 𝑥𝑤 𝑅 𝑥 ) → ( ¬ 𝑧 = 𝑤 → ∀ 𝑦 ( 𝑦 𝑅 𝑧 → ¬ 𝑦 𝑅 𝑤 ) ) ) ↔ ( ( 𝑧 ∈ ( 𝐹𝑥 ) ∧ 𝑤 ∈ ( 𝐹𝑥 ) ) → ( ( 𝐹𝑧 ) ≠ ( 𝐹𝑤 ) → ( ( 𝐹𝑧 ) ∩ ( 𝐹𝑤 ) ) = ∅ ) ) )
57 56 2albii ( ∀ 𝑧𝑤 ( ( 𝑧 𝑅 𝑥𝑤 𝑅 𝑥 ) → ( ¬ 𝑧 = 𝑤 → ∀ 𝑦 ( 𝑦 𝑅 𝑧 → ¬ 𝑦 𝑅 𝑤 ) ) ) ↔ ∀ 𝑧𝑤 ( ( 𝑧 ∈ ( 𝐹𝑥 ) ∧ 𝑤 ∈ ( 𝐹𝑥 ) ) → ( ( 𝐹𝑧 ) ≠ ( 𝐹𝑤 ) → ( ( 𝐹𝑧 ) ∩ ( 𝐹𝑤 ) ) = ∅ ) ) )
58 36 57 bitr4i ( ∀ 𝑡 ∈ ( 𝐹 “ ( 𝐹𝑥 ) ) ∀ 𝑞 ∈ ( 𝐹 “ ( 𝐹𝑥 ) ) ( 𝑡𝑞 → ( 𝑡𝑞 ) = ∅ ) ↔ ∀ 𝑧𝑤 ( ( 𝑧 𝑅 𝑥𝑤 𝑅 𝑥 ) → ( ¬ 𝑧 = 𝑤 → ∀ 𝑦 ( 𝑦 𝑅 𝑧 → ¬ 𝑦 𝑅 𝑤 ) ) ) )
59 f1ofun ( 𝐹 : V –1-1-onto→ V → Fun 𝐹 )
60 fvex ( 𝐹𝑥 ) ∈ V
61 60 funimaex ( Fun 𝐹 → ( 𝐹 “ ( 𝐹𝑥 ) ) ∈ V )
62 1 59 61 mp2b ( 𝐹 “ ( 𝐹𝑥 ) ) ∈ V
63 raleq ( 𝑟 = ( 𝐹 “ ( 𝐹𝑥 ) ) → ( ∀ 𝑡𝑟 𝑡 ≠ ∅ ↔ ∀ 𝑡 ∈ ( 𝐹 “ ( 𝐹𝑥 ) ) 𝑡 ≠ ∅ ) )
64 raleq ( 𝑟 = ( 𝐹 “ ( 𝐹𝑥 ) ) → ( ∀ 𝑞𝑟 ( 𝑡𝑞 → ( 𝑡𝑞 ) = ∅ ) ↔ ∀ 𝑞 ∈ ( 𝐹 “ ( 𝐹𝑥 ) ) ( 𝑡𝑞 → ( 𝑡𝑞 ) = ∅ ) ) )
65 64 raleqbi1dv ( 𝑟 = ( 𝐹 “ ( 𝐹𝑥 ) ) → ( ∀ 𝑡𝑟𝑞𝑟 ( 𝑡𝑞 → ( 𝑡𝑞 ) = ∅ ) ↔ ∀ 𝑡 ∈ ( 𝐹 “ ( 𝐹𝑥 ) ) ∀ 𝑞 ∈ ( 𝐹 “ ( 𝐹𝑥 ) ) ( 𝑡𝑞 → ( 𝑡𝑞 ) = ∅ ) ) )
66 63 65 anbi12d ( 𝑟 = ( 𝐹 “ ( 𝐹𝑥 ) ) → ( ( ∀ 𝑡𝑟 𝑡 ≠ ∅ ∧ ∀ 𝑡𝑟𝑞𝑟 ( 𝑡𝑞 → ( 𝑡𝑞 ) = ∅ ) ) ↔ ( ∀ 𝑡 ∈ ( 𝐹 “ ( 𝐹𝑥 ) ) 𝑡 ≠ ∅ ∧ ∀ 𝑡 ∈ ( 𝐹 “ ( 𝐹𝑥 ) ) ∀ 𝑞 ∈ ( 𝐹 “ ( 𝐹𝑥 ) ) ( 𝑡𝑞 → ( 𝑡𝑞 ) = ∅ ) ) ) )
67 raleq ( 𝑟 = ( 𝐹 “ ( 𝐹𝑥 ) ) → ( ∀ 𝑡𝑟 ∃! 𝑣 𝑣 ∈ ( 𝑡𝑠 ) ↔ ∀ 𝑡 ∈ ( 𝐹 “ ( 𝐹𝑥 ) ) ∃! 𝑣 𝑣 ∈ ( 𝑡𝑠 ) ) )
68 67 exbidv ( 𝑟 = ( 𝐹 “ ( 𝐹𝑥 ) ) → ( ∃ 𝑠𝑡𝑟 ∃! 𝑣 𝑣 ∈ ( 𝑡𝑠 ) ↔ ∃ 𝑠𝑡 ∈ ( 𝐹 “ ( 𝐹𝑥 ) ) ∃! 𝑣 𝑣 ∈ ( 𝑡𝑠 ) ) )
69 66 68 imbi12d ( 𝑟 = ( 𝐹 “ ( 𝐹𝑥 ) ) → ( ( ( ∀ 𝑡𝑟 𝑡 ≠ ∅ ∧ ∀ 𝑡𝑟𝑞𝑟 ( 𝑡𝑞 → ( 𝑡𝑞 ) = ∅ ) ) → ∃ 𝑠𝑡𝑟 ∃! 𝑣 𝑣 ∈ ( 𝑡𝑠 ) ) ↔ ( ( ∀ 𝑡 ∈ ( 𝐹 “ ( 𝐹𝑥 ) ) 𝑡 ≠ ∅ ∧ ∀ 𝑡 ∈ ( 𝐹 “ ( 𝐹𝑥 ) ) ∀ 𝑞 ∈ ( 𝐹 “ ( 𝐹𝑥 ) ) ( 𝑡𝑞 → ( 𝑡𝑞 ) = ∅ ) ) → ∃ 𝑠𝑡 ∈ ( 𝐹 “ ( 𝐹𝑥 ) ) ∃! 𝑣 𝑣 ∈ ( 𝑡𝑠 ) ) ) )
70 ac8 ( ( ∀ 𝑡𝑟 𝑡 ≠ ∅ ∧ ∀ 𝑡𝑟𝑞𝑟 ( 𝑡𝑞 → ( 𝑡𝑞 ) = ∅ ) ) → ∃ 𝑠𝑡𝑟 ∃! 𝑣 𝑣 ∈ ( 𝑡𝑠 ) )
71 62 69 70 vtocl ( ( ∀ 𝑡 ∈ ( 𝐹 “ ( 𝐹𝑥 ) ) 𝑡 ≠ ∅ ∧ ∀ 𝑡 ∈ ( 𝐹 “ ( 𝐹𝑥 ) ) ∀ 𝑞 ∈ ( 𝐹 “ ( 𝐹𝑥 ) ) ( 𝑡𝑞 → ( 𝑡𝑞 ) = ∅ ) ) → ∃ 𝑠𝑡 ∈ ( 𝐹 “ ( 𝐹𝑥 ) ) ∃! 𝑣 𝑣 ∈ ( 𝑡𝑠 ) )
72 20 58 71 syl2anbr ( ( ∀ 𝑧 ( 𝑧 𝑅 𝑥 → ∃ 𝑤 𝑤 𝑅 𝑧 ) ∧ ∀ 𝑧𝑤 ( ( 𝑧 𝑅 𝑥𝑤 𝑅 𝑥 ) → ( ¬ 𝑧 = 𝑤 → ∀ 𝑦 ( 𝑦 𝑅 𝑧 → ¬ 𝑦 𝑅 𝑤 ) ) ) ) → ∃ 𝑠𝑡 ∈ ( 𝐹 “ ( 𝐹𝑥 ) ) ∃! 𝑣 𝑣 ∈ ( 𝑡𝑠 ) )
73 ineq1 ( 𝑡 = ( 𝐹𝑧 ) → ( 𝑡𝑠 ) = ( ( 𝐹𝑧 ) ∩ 𝑠 ) )
74 73 eleq2d ( 𝑡 = ( 𝐹𝑧 ) → ( 𝑣 ∈ ( 𝑡𝑠 ) ↔ 𝑣 ∈ ( ( 𝐹𝑧 ) ∩ 𝑠 ) ) )
75 74 eubidv ( 𝑡 = ( 𝐹𝑧 ) → ( ∃! 𝑣 𝑣 ∈ ( 𝑡𝑠 ) ↔ ∃! 𝑣 𝑣 ∈ ( ( 𝐹𝑧 ) ∩ 𝑠 ) ) )
76 75 ralima ( ( 𝐹 Fn V ∧ ( 𝐹𝑥 ) ⊆ V ) → ( ∀ 𝑡 ∈ ( 𝐹 “ ( 𝐹𝑥 ) ) ∃! 𝑣 𝑣 ∈ ( 𝑡𝑠 ) ↔ ∀ 𝑧 ∈ ( 𝐹𝑥 ) ∃! 𝑣 𝑣 ∈ ( ( 𝐹𝑧 ) ∩ 𝑠 ) ) )
77 5 6 76 mp2an ( ∀ 𝑡 ∈ ( 𝐹 “ ( 𝐹𝑥 ) ) ∃! 𝑣 𝑣 ∈ ( 𝑡𝑠 ) ↔ ∀ 𝑧 ∈ ( 𝐹𝑥 ) ∃! 𝑣 𝑣 ∈ ( ( 𝐹𝑧 ) ∩ 𝑠 ) )
78 df-ral ( ∀ 𝑧 ∈ ( 𝐹𝑥 ) ∃! 𝑣 𝑣 ∈ ( ( 𝐹𝑧 ) ∩ 𝑠 ) ↔ ∀ 𝑧 ( 𝑧 ∈ ( 𝐹𝑥 ) → ∃! 𝑣 𝑣 ∈ ( ( 𝐹𝑧 ) ∩ 𝑠 ) ) )
79 77 78 bitri ( ∀ 𝑡 ∈ ( 𝐹 “ ( 𝐹𝑥 ) ) ∃! 𝑣 𝑣 ∈ ( 𝑡𝑠 ) ↔ ∀ 𝑧 ( 𝑧 ∈ ( 𝐹𝑥 ) → ∃! 𝑣 𝑣 ∈ ( ( 𝐹𝑧 ) ∩ 𝑠 ) ) )
80 fvex ( 𝐹𝑠 ) ∈ V
81 12 a1i ( 𝑦 = ( 𝐹𝑠 ) → ( 𝑧 𝑅 𝑥𝑧 ∈ ( 𝐹𝑥 ) ) )
82 vex 𝑣 ∈ V
83 1 2 82 10 brpermmodel ( 𝑣 𝑅 𝑧𝑣 ∈ ( 𝐹𝑧 ) )
84 83 a1i ( 𝑦 = ( 𝐹𝑠 ) → ( 𝑣 𝑅 𝑧𝑣 ∈ ( 𝐹𝑧 ) ) )
85 breq2 ( 𝑦 = ( 𝐹𝑠 ) → ( 𝑣 𝑅 𝑦𝑣 𝑅 ( 𝐹𝑠 ) ) )
86 vex 𝑠 ∈ V
87 1 2 82 86 brpermmodelcnv ( 𝑣 𝑅 ( 𝐹𝑠 ) ↔ 𝑣𝑠 )
88 85 87 bitrdi ( 𝑦 = ( 𝐹𝑠 ) → ( 𝑣 𝑅 𝑦𝑣𝑠 ) )
89 84 88 anbi12d ( 𝑦 = ( 𝐹𝑠 ) → ( ( 𝑣 𝑅 𝑧𝑣 𝑅 𝑦 ) ↔ ( 𝑣 ∈ ( 𝐹𝑧 ) ∧ 𝑣𝑠 ) ) )
90 89 bibi1d ( 𝑦 = ( 𝐹𝑠 ) → ( ( ( 𝑣 𝑅 𝑧𝑣 𝑅 𝑦 ) ↔ 𝑣 = 𝑤 ) ↔ ( ( 𝑣 ∈ ( 𝐹𝑧 ) ∧ 𝑣𝑠 ) ↔ 𝑣 = 𝑤 ) ) )
91 90 albidv ( 𝑦 = ( 𝐹𝑠 ) → ( ∀ 𝑣 ( ( 𝑣 𝑅 𝑧𝑣 𝑅 𝑦 ) ↔ 𝑣 = 𝑤 ) ↔ ∀ 𝑣 ( ( 𝑣 ∈ ( 𝐹𝑧 ) ∧ 𝑣𝑠 ) ↔ 𝑣 = 𝑤 ) ) )
92 91 exbidv ( 𝑦 = ( 𝐹𝑠 ) → ( ∃ 𝑤𝑣 ( ( 𝑣 𝑅 𝑧𝑣 𝑅 𝑦 ) ↔ 𝑣 = 𝑤 ) ↔ ∃ 𝑤𝑣 ( ( 𝑣 ∈ ( 𝐹𝑧 ) ∧ 𝑣𝑠 ) ↔ 𝑣 = 𝑤 ) ) )
93 elin ( 𝑣 ∈ ( ( 𝐹𝑧 ) ∩ 𝑠 ) ↔ ( 𝑣 ∈ ( 𝐹𝑧 ) ∧ 𝑣𝑠 ) )
94 93 eubii ( ∃! 𝑣 𝑣 ∈ ( ( 𝐹𝑧 ) ∩ 𝑠 ) ↔ ∃! 𝑣 ( 𝑣 ∈ ( 𝐹𝑧 ) ∧ 𝑣𝑠 ) )
95 eu6 ( ∃! 𝑣 ( 𝑣 ∈ ( 𝐹𝑧 ) ∧ 𝑣𝑠 ) ↔ ∃ 𝑤𝑣 ( ( 𝑣 ∈ ( 𝐹𝑧 ) ∧ 𝑣𝑠 ) ↔ 𝑣 = 𝑤 ) )
96 94 95 bitri ( ∃! 𝑣 𝑣 ∈ ( ( 𝐹𝑧 ) ∩ 𝑠 ) ↔ ∃ 𝑤𝑣 ( ( 𝑣 ∈ ( 𝐹𝑧 ) ∧ 𝑣𝑠 ) ↔ 𝑣 = 𝑤 ) )
97 92 96 bitr4di ( 𝑦 = ( 𝐹𝑠 ) → ( ∃ 𝑤𝑣 ( ( 𝑣 𝑅 𝑧𝑣 𝑅 𝑦 ) ↔ 𝑣 = 𝑤 ) ↔ ∃! 𝑣 𝑣 ∈ ( ( 𝐹𝑧 ) ∩ 𝑠 ) ) )
98 81 97 imbi12d ( 𝑦 = ( 𝐹𝑠 ) → ( ( 𝑧 𝑅 𝑥 → ∃ 𝑤𝑣 ( ( 𝑣 𝑅 𝑧𝑣 𝑅 𝑦 ) ↔ 𝑣 = 𝑤 ) ) ↔ ( 𝑧 ∈ ( 𝐹𝑥 ) → ∃! 𝑣 𝑣 ∈ ( ( 𝐹𝑧 ) ∩ 𝑠 ) ) ) )
99 98 albidv ( 𝑦 = ( 𝐹𝑠 ) → ( ∀ 𝑧 ( 𝑧 𝑅 𝑥 → ∃ 𝑤𝑣 ( ( 𝑣 𝑅 𝑧𝑣 𝑅 𝑦 ) ↔ 𝑣 = 𝑤 ) ) ↔ ∀ 𝑧 ( 𝑧 ∈ ( 𝐹𝑥 ) → ∃! 𝑣 𝑣 ∈ ( ( 𝐹𝑧 ) ∩ 𝑠 ) ) ) )
100 80 99 spcev ( ∀ 𝑧 ( 𝑧 ∈ ( 𝐹𝑥 ) → ∃! 𝑣 𝑣 ∈ ( ( 𝐹𝑧 ) ∩ 𝑠 ) ) → ∃ 𝑦𝑧 ( 𝑧 𝑅 𝑥 → ∃ 𝑤𝑣 ( ( 𝑣 𝑅 𝑧𝑣 𝑅 𝑦 ) ↔ 𝑣 = 𝑤 ) ) )
101 79 100 sylbi ( ∀ 𝑡 ∈ ( 𝐹 “ ( 𝐹𝑥 ) ) ∃! 𝑣 𝑣 ∈ ( 𝑡𝑠 ) → ∃ 𝑦𝑧 ( 𝑧 𝑅 𝑥 → ∃ 𝑤𝑣 ( ( 𝑣 𝑅 𝑧𝑣 𝑅 𝑦 ) ↔ 𝑣 = 𝑤 ) ) )
102 101 exlimiv ( ∃ 𝑠𝑡 ∈ ( 𝐹 “ ( 𝐹𝑥 ) ) ∃! 𝑣 𝑣 ∈ ( 𝑡𝑠 ) → ∃ 𝑦𝑧 ( 𝑧 𝑅 𝑥 → ∃ 𝑤𝑣 ( ( 𝑣 𝑅 𝑧𝑣 𝑅 𝑦 ) ↔ 𝑣 = 𝑤 ) ) )
103 72 102 syl ( ( ∀ 𝑧 ( 𝑧 𝑅 𝑥 → ∃ 𝑤 𝑤 𝑅 𝑧 ) ∧ ∀ 𝑧𝑤 ( ( 𝑧 𝑅 𝑥𝑤 𝑅 𝑥 ) → ( ¬ 𝑧 = 𝑤 → ∀ 𝑦 ( 𝑦 𝑅 𝑧 → ¬ 𝑦 𝑅 𝑤 ) ) ) ) → ∃ 𝑦𝑧 ( 𝑧 𝑅 𝑥 → ∃ 𝑤𝑣 ( ( 𝑣 𝑅 𝑧𝑣 𝑅 𝑦 ) ↔ 𝑣 = 𝑤 ) ) )