Metamath Proof Explorer


Theorem dfac5lem4

Description: Lemma for dfac5 . (Contributed by NM, 11-Apr-2004)

Ref Expression
Hypotheses dfac5lem.1 𝐴 = { 𝑢 ∣ ( 𝑢 ≠ ∅ ∧ ∃ 𝑡 𝑢 = ( { 𝑡 } × 𝑡 ) ) }
dfac5lem.2 𝐵 = ( 𝐴𝑦 )
dfac5lem.3 ( 𝜑 ↔ ∀ 𝑥 ( ( ∀ 𝑧𝑥 𝑧 ≠ ∅ ∧ ∀ 𝑧𝑥𝑤𝑥 ( 𝑧𝑤 → ( 𝑧𝑤 ) = ∅ ) ) → ∃ 𝑦𝑧𝑥 ∃! 𝑣 𝑣 ∈ ( 𝑧𝑦 ) ) )
Assertion dfac5lem4 ( 𝜑 → ∃ 𝑦𝑧𝐴 ∃! 𝑣 𝑣 ∈ ( 𝑧𝑦 ) )

Proof

Step Hyp Ref Expression
1 dfac5lem.1 𝐴 = { 𝑢 ∣ ( 𝑢 ≠ ∅ ∧ ∃ 𝑡 𝑢 = ( { 𝑡 } × 𝑡 ) ) }
2 dfac5lem.2 𝐵 = ( 𝐴𝑦 )
3 dfac5lem.3 ( 𝜑 ↔ ∀ 𝑥 ( ( ∀ 𝑧𝑥 𝑧 ≠ ∅ ∧ ∀ 𝑧𝑥𝑤𝑥 ( 𝑧𝑤 → ( 𝑧𝑤 ) = ∅ ) ) → ∃ 𝑦𝑧𝑥 ∃! 𝑣 𝑣 ∈ ( 𝑧𝑦 ) ) )
4 vex 𝑧 ∈ V
5 neeq1 ( 𝑢 = 𝑧 → ( 𝑢 ≠ ∅ ↔ 𝑧 ≠ ∅ ) )
6 eqeq1 ( 𝑢 = 𝑧 → ( 𝑢 = ( { 𝑡 } × 𝑡 ) ↔ 𝑧 = ( { 𝑡 } × 𝑡 ) ) )
7 6 rexbidv ( 𝑢 = 𝑧 → ( ∃ 𝑡 𝑢 = ( { 𝑡 } × 𝑡 ) ↔ ∃ 𝑡 𝑧 = ( { 𝑡 } × 𝑡 ) ) )
8 5 7 anbi12d ( 𝑢 = 𝑧 → ( ( 𝑢 ≠ ∅ ∧ ∃ 𝑡 𝑢 = ( { 𝑡 } × 𝑡 ) ) ↔ ( 𝑧 ≠ ∅ ∧ ∃ 𝑡 𝑧 = ( { 𝑡 } × 𝑡 ) ) ) )
9 4 8 elab ( 𝑧 ∈ { 𝑢 ∣ ( 𝑢 ≠ ∅ ∧ ∃ 𝑡 𝑢 = ( { 𝑡 } × 𝑡 ) ) } ↔ ( 𝑧 ≠ ∅ ∧ ∃ 𝑡 𝑧 = ( { 𝑡 } × 𝑡 ) ) )
10 9 simplbi ( 𝑧 ∈ { 𝑢 ∣ ( 𝑢 ≠ ∅ ∧ ∃ 𝑡 𝑢 = ( { 𝑡 } × 𝑡 ) ) } → 𝑧 ≠ ∅ )
11 10 1 eleq2s ( 𝑧𝐴𝑧 ≠ ∅ )
12 11 rgen 𝑧𝐴 𝑧 ≠ ∅
13 df-an ( ( 𝑥𝑧𝑥𝑤 ) ↔ ¬ ( 𝑥𝑧 → ¬ 𝑥𝑤 ) )
14 4 8 1 elab2 ( 𝑧𝐴 ↔ ( 𝑧 ≠ ∅ ∧ ∃ 𝑡 𝑧 = ( { 𝑡 } × 𝑡 ) ) )
15 14 simprbi ( 𝑧𝐴 → ∃ 𝑡 𝑧 = ( { 𝑡 } × 𝑡 ) )
16 vex 𝑤 ∈ V
17 neeq1 ( 𝑢 = 𝑤 → ( 𝑢 ≠ ∅ ↔ 𝑤 ≠ ∅ ) )
18 eqeq1 ( 𝑢 = 𝑤 → ( 𝑢 = ( { 𝑡 } × 𝑡 ) ↔ 𝑤 = ( { 𝑡 } × 𝑡 ) ) )
19 18 rexbidv ( 𝑢 = 𝑤 → ( ∃ 𝑡 𝑢 = ( { 𝑡 } × 𝑡 ) ↔ ∃ 𝑡 𝑤 = ( { 𝑡 } × 𝑡 ) ) )
20 17 19 anbi12d ( 𝑢 = 𝑤 → ( ( 𝑢 ≠ ∅ ∧ ∃ 𝑡 𝑢 = ( { 𝑡 } × 𝑡 ) ) ↔ ( 𝑤 ≠ ∅ ∧ ∃ 𝑡 𝑤 = ( { 𝑡 } × 𝑡 ) ) ) )
21 16 20 1 elab2 ( 𝑤𝐴 ↔ ( 𝑤 ≠ ∅ ∧ ∃ 𝑡 𝑤 = ( { 𝑡 } × 𝑡 ) ) )
22 21 simprbi ( 𝑤𝐴 → ∃ 𝑡 𝑤 = ( { 𝑡 } × 𝑡 ) )
23 sneq ( 𝑡 = 𝑔 → { 𝑡 } = { 𝑔 } )
24 23 xpeq1d ( 𝑡 = 𝑔 → ( { 𝑡 } × 𝑡 ) = ( { 𝑔 } × 𝑡 ) )
25 xpeq2 ( 𝑡 = 𝑔 → ( { 𝑔 } × 𝑡 ) = ( { 𝑔 } × 𝑔 ) )
26 24 25 eqtrd ( 𝑡 = 𝑔 → ( { 𝑡 } × 𝑡 ) = ( { 𝑔 } × 𝑔 ) )
27 26 eqeq2d ( 𝑡 = 𝑔 → ( 𝑤 = ( { 𝑡 } × 𝑡 ) ↔ 𝑤 = ( { 𝑔 } × 𝑔 ) ) )
28 27 cbvrexvw ( ∃ 𝑡 𝑤 = ( { 𝑡 } × 𝑡 ) ↔ ∃ 𝑔 𝑤 = ( { 𝑔 } × 𝑔 ) )
29 22 28 sylib ( 𝑤𝐴 → ∃ 𝑔 𝑤 = ( { 𝑔 } × 𝑔 ) )
30 eleq2 ( 𝑧 = ( { 𝑡 } × 𝑡 ) → ( 𝑥𝑧𝑥 ∈ ( { 𝑡 } × 𝑡 ) ) )
31 elxp ( 𝑥 ∈ ( { 𝑡 } × 𝑡 ) ↔ ∃ 𝑢𝑣 ( 𝑥 = ⟨ 𝑢 , 𝑣 ⟩ ∧ ( 𝑢 ∈ { 𝑡 } ∧ 𝑣𝑡 ) ) )
32 excom ( ∃ 𝑢𝑣 ( 𝑥 = ⟨ 𝑢 , 𝑣 ⟩ ∧ ( 𝑢 ∈ { 𝑡 } ∧ 𝑣𝑡 ) ) ↔ ∃ 𝑣𝑢 ( 𝑥 = ⟨ 𝑢 , 𝑣 ⟩ ∧ ( 𝑢 ∈ { 𝑡 } ∧ 𝑣𝑡 ) ) )
33 31 32 bitri ( 𝑥 ∈ ( { 𝑡 } × 𝑡 ) ↔ ∃ 𝑣𝑢 ( 𝑥 = ⟨ 𝑢 , 𝑣 ⟩ ∧ ( 𝑢 ∈ { 𝑡 } ∧ 𝑣𝑡 ) ) )
34 30 33 bitrdi ( 𝑧 = ( { 𝑡 } × 𝑡 ) → ( 𝑥𝑧 ↔ ∃ 𝑣𝑢 ( 𝑥 = ⟨ 𝑢 , 𝑣 ⟩ ∧ ( 𝑢 ∈ { 𝑡 } ∧ 𝑣𝑡 ) ) ) )
35 eleq2 ( 𝑤 = ( { 𝑔 } × 𝑔 ) → ( 𝑥𝑤𝑥 ∈ ( { 𝑔 } × 𝑔 ) ) )
36 elxp ( 𝑥 ∈ ( { 𝑔 } × 𝑔 ) ↔ ∃ 𝑢𝑦 ( 𝑥 = ⟨ 𝑢 , 𝑦 ⟩ ∧ ( 𝑢 ∈ { 𝑔 } ∧ 𝑦𝑔 ) ) )
37 excom ( ∃ 𝑢𝑦 ( 𝑥 = ⟨ 𝑢 , 𝑦 ⟩ ∧ ( 𝑢 ∈ { 𝑔 } ∧ 𝑦𝑔 ) ) ↔ ∃ 𝑦𝑢 ( 𝑥 = ⟨ 𝑢 , 𝑦 ⟩ ∧ ( 𝑢 ∈ { 𝑔 } ∧ 𝑦𝑔 ) ) )
38 36 37 bitri ( 𝑥 ∈ ( { 𝑔 } × 𝑔 ) ↔ ∃ 𝑦𝑢 ( 𝑥 = ⟨ 𝑢 , 𝑦 ⟩ ∧ ( 𝑢 ∈ { 𝑔 } ∧ 𝑦𝑔 ) ) )
39 35 38 bitrdi ( 𝑤 = ( { 𝑔 } × 𝑔 ) → ( 𝑥𝑤 ↔ ∃ 𝑦𝑢 ( 𝑥 = ⟨ 𝑢 , 𝑦 ⟩ ∧ ( 𝑢 ∈ { 𝑔 } ∧ 𝑦𝑔 ) ) ) )
40 34 39 bi2anan9 ( ( 𝑧 = ( { 𝑡 } × 𝑡 ) ∧ 𝑤 = ( { 𝑔 } × 𝑔 ) ) → ( ( 𝑥𝑧𝑥𝑤 ) ↔ ( ∃ 𝑣𝑢 ( 𝑥 = ⟨ 𝑢 , 𝑣 ⟩ ∧ ( 𝑢 ∈ { 𝑡 } ∧ 𝑣𝑡 ) ) ∧ ∃ 𝑦𝑢 ( 𝑥 = ⟨ 𝑢 , 𝑦 ⟩ ∧ ( 𝑢 ∈ { 𝑔 } ∧ 𝑦𝑔 ) ) ) ) )
41 exdistrv ( ∃ 𝑣𝑦 ( ∃ 𝑢 ( 𝑥 = ⟨ 𝑢 , 𝑣 ⟩ ∧ ( 𝑢 ∈ { 𝑡 } ∧ 𝑣𝑡 ) ) ∧ ∃ 𝑢 ( 𝑥 = ⟨ 𝑢 , 𝑦 ⟩ ∧ ( 𝑢 ∈ { 𝑔 } ∧ 𝑦𝑔 ) ) ) ↔ ( ∃ 𝑣𝑢 ( 𝑥 = ⟨ 𝑢 , 𝑣 ⟩ ∧ ( 𝑢 ∈ { 𝑡 } ∧ 𝑣𝑡 ) ) ∧ ∃ 𝑦𝑢 ( 𝑥 = ⟨ 𝑢 , 𝑦 ⟩ ∧ ( 𝑢 ∈ { 𝑔 } ∧ 𝑦𝑔 ) ) ) )
42 40 41 bitr4di ( ( 𝑧 = ( { 𝑡 } × 𝑡 ) ∧ 𝑤 = ( { 𝑔 } × 𝑔 ) ) → ( ( 𝑥𝑧𝑥𝑤 ) ↔ ∃ 𝑣𝑦 ( ∃ 𝑢 ( 𝑥 = ⟨ 𝑢 , 𝑣 ⟩ ∧ ( 𝑢 ∈ { 𝑡 } ∧ 𝑣𝑡 ) ) ∧ ∃ 𝑢 ( 𝑥 = ⟨ 𝑢 , 𝑦 ⟩ ∧ ( 𝑢 ∈ { 𝑔 } ∧ 𝑦𝑔 ) ) ) ) )
43 velsn ( 𝑢 ∈ { 𝑡 } ↔ 𝑢 = 𝑡 )
44 opeq1 ( 𝑢 = 𝑡 → ⟨ 𝑢 , 𝑣 ⟩ = ⟨ 𝑡 , 𝑣 ⟩ )
45 44 eqeq2d ( 𝑢 = 𝑡 → ( 𝑥 = ⟨ 𝑢 , 𝑣 ⟩ ↔ 𝑥 = ⟨ 𝑡 , 𝑣 ⟩ ) )
46 45 biimpac ( ( 𝑥 = ⟨ 𝑢 , 𝑣 ⟩ ∧ 𝑢 = 𝑡 ) → 𝑥 = ⟨ 𝑡 , 𝑣 ⟩ )
47 43 46 sylan2b ( ( 𝑥 = ⟨ 𝑢 , 𝑣 ⟩ ∧ 𝑢 ∈ { 𝑡 } ) → 𝑥 = ⟨ 𝑡 , 𝑣 ⟩ )
48 47 adantrr ( ( 𝑥 = ⟨ 𝑢 , 𝑣 ⟩ ∧ ( 𝑢 ∈ { 𝑡 } ∧ 𝑣𝑡 ) ) → 𝑥 = ⟨ 𝑡 , 𝑣 ⟩ )
49 48 exlimiv ( ∃ 𝑢 ( 𝑥 = ⟨ 𝑢 , 𝑣 ⟩ ∧ ( 𝑢 ∈ { 𝑡 } ∧ 𝑣𝑡 ) ) → 𝑥 = ⟨ 𝑡 , 𝑣 ⟩ )
50 velsn ( 𝑢 ∈ { 𝑔 } ↔ 𝑢 = 𝑔 )
51 opeq1 ( 𝑢 = 𝑔 → ⟨ 𝑢 , 𝑦 ⟩ = ⟨ 𝑔 , 𝑦 ⟩ )
52 51 eqeq2d ( 𝑢 = 𝑔 → ( 𝑥 = ⟨ 𝑢 , 𝑦 ⟩ ↔ 𝑥 = ⟨ 𝑔 , 𝑦 ⟩ ) )
53 52 biimpac ( ( 𝑥 = ⟨ 𝑢 , 𝑦 ⟩ ∧ 𝑢 = 𝑔 ) → 𝑥 = ⟨ 𝑔 , 𝑦 ⟩ )
54 50 53 sylan2b ( ( 𝑥 = ⟨ 𝑢 , 𝑦 ⟩ ∧ 𝑢 ∈ { 𝑔 } ) → 𝑥 = ⟨ 𝑔 , 𝑦 ⟩ )
55 54 adantrr ( ( 𝑥 = ⟨ 𝑢 , 𝑦 ⟩ ∧ ( 𝑢 ∈ { 𝑔 } ∧ 𝑦𝑔 ) ) → 𝑥 = ⟨ 𝑔 , 𝑦 ⟩ )
56 55 exlimiv ( ∃ 𝑢 ( 𝑥 = ⟨ 𝑢 , 𝑦 ⟩ ∧ ( 𝑢 ∈ { 𝑔 } ∧ 𝑦𝑔 ) ) → 𝑥 = ⟨ 𝑔 , 𝑦 ⟩ )
57 49 56 sylan9req ( ( ∃ 𝑢 ( 𝑥 = ⟨ 𝑢 , 𝑣 ⟩ ∧ ( 𝑢 ∈ { 𝑡 } ∧ 𝑣𝑡 ) ) ∧ ∃ 𝑢 ( 𝑥 = ⟨ 𝑢 , 𝑦 ⟩ ∧ ( 𝑢 ∈ { 𝑔 } ∧ 𝑦𝑔 ) ) ) → ⟨ 𝑡 , 𝑣 ⟩ = ⟨ 𝑔 , 𝑦 ⟩ )
58 vex 𝑡 ∈ V
59 vex 𝑣 ∈ V
60 58 59 opth1 ( ⟨ 𝑡 , 𝑣 ⟩ = ⟨ 𝑔 , 𝑦 ⟩ → 𝑡 = 𝑔 )
61 57 60 syl ( ( ∃ 𝑢 ( 𝑥 = ⟨ 𝑢 , 𝑣 ⟩ ∧ ( 𝑢 ∈ { 𝑡 } ∧ 𝑣𝑡 ) ) ∧ ∃ 𝑢 ( 𝑥 = ⟨ 𝑢 , 𝑦 ⟩ ∧ ( 𝑢 ∈ { 𝑔 } ∧ 𝑦𝑔 ) ) ) → 𝑡 = 𝑔 )
62 61 exlimivv ( ∃ 𝑣𝑦 ( ∃ 𝑢 ( 𝑥 = ⟨ 𝑢 , 𝑣 ⟩ ∧ ( 𝑢 ∈ { 𝑡 } ∧ 𝑣𝑡 ) ) ∧ ∃ 𝑢 ( 𝑥 = ⟨ 𝑢 , 𝑦 ⟩ ∧ ( 𝑢 ∈ { 𝑔 } ∧ 𝑦𝑔 ) ) ) → 𝑡 = 𝑔 )
63 42 62 syl6bi ( ( 𝑧 = ( { 𝑡 } × 𝑡 ) ∧ 𝑤 = ( { 𝑔 } × 𝑔 ) ) → ( ( 𝑥𝑧𝑥𝑤 ) → 𝑡 = 𝑔 ) )
64 63 26 syl6 ( ( 𝑧 = ( { 𝑡 } × 𝑡 ) ∧ 𝑤 = ( { 𝑔 } × 𝑔 ) ) → ( ( 𝑥𝑧𝑥𝑤 ) → ( { 𝑡 } × 𝑡 ) = ( { 𝑔 } × 𝑔 ) ) )
65 eqeq12 ( ( 𝑧 = ( { 𝑡 } × 𝑡 ) ∧ 𝑤 = ( { 𝑔 } × 𝑔 ) ) → ( 𝑧 = 𝑤 ↔ ( { 𝑡 } × 𝑡 ) = ( { 𝑔 } × 𝑔 ) ) )
66 64 65 sylibrd ( ( 𝑧 = ( { 𝑡 } × 𝑡 ) ∧ 𝑤 = ( { 𝑔 } × 𝑔 ) ) → ( ( 𝑥𝑧𝑥𝑤 ) → 𝑧 = 𝑤 ) )
67 66 ex ( 𝑧 = ( { 𝑡 } × 𝑡 ) → ( 𝑤 = ( { 𝑔 } × 𝑔 ) → ( ( 𝑥𝑧𝑥𝑤 ) → 𝑧 = 𝑤 ) ) )
68 67 rexlimivw ( ∃ 𝑡 𝑧 = ( { 𝑡 } × 𝑡 ) → ( 𝑤 = ( { 𝑔 } × 𝑔 ) → ( ( 𝑥𝑧𝑥𝑤 ) → 𝑧 = 𝑤 ) ) )
69 68 rexlimdvw ( ∃ 𝑡 𝑧 = ( { 𝑡 } × 𝑡 ) → ( ∃ 𝑔 𝑤 = ( { 𝑔 } × 𝑔 ) → ( ( 𝑥𝑧𝑥𝑤 ) → 𝑧 = 𝑤 ) ) )
70 69 imp ( ( ∃ 𝑡 𝑧 = ( { 𝑡 } × 𝑡 ) ∧ ∃ 𝑔 𝑤 = ( { 𝑔 } × 𝑔 ) ) → ( ( 𝑥𝑧𝑥𝑤 ) → 𝑧 = 𝑤 ) )
71 15 29 70 syl2an ( ( 𝑧𝐴𝑤𝐴 ) → ( ( 𝑥𝑧𝑥𝑤 ) → 𝑧 = 𝑤 ) )
72 13 71 syl5bir ( ( 𝑧𝐴𝑤𝐴 ) → ( ¬ ( 𝑥𝑧 → ¬ 𝑥𝑤 ) → 𝑧 = 𝑤 ) )
73 72 necon1ad ( ( 𝑧𝐴𝑤𝐴 ) → ( 𝑧𝑤 → ( 𝑥𝑧 → ¬ 𝑥𝑤 ) ) )
74 73 alrimdv ( ( 𝑧𝐴𝑤𝐴 ) → ( 𝑧𝑤 → ∀ 𝑥 ( 𝑥𝑧 → ¬ 𝑥𝑤 ) ) )
75 disj1 ( ( 𝑧𝑤 ) = ∅ ↔ ∀ 𝑥 ( 𝑥𝑧 → ¬ 𝑥𝑤 ) )
76 74 75 syl6ibr ( ( 𝑧𝐴𝑤𝐴 ) → ( 𝑧𝑤 → ( 𝑧𝑤 ) = ∅ ) )
77 76 rgen2 𝑧𝐴𝑤𝐴 ( 𝑧𝑤 → ( 𝑧𝑤 ) = ∅ )
78 vex ∈ V
79 vuniex ∈ V
80 78 79 xpex ( × ) ∈ V
81 80 pwex 𝒫 ( × ) ∈ V
82 snssi ( 𝑡 → { 𝑡 } ⊆ )
83 elssuni ( 𝑡𝑡 )
84 xpss12 ( ( { 𝑡 } ⊆ 𝑡 ) → ( { 𝑡 } × 𝑡 ) ⊆ ( × ) )
85 82 83 84 syl2anc ( 𝑡 → ( { 𝑡 } × 𝑡 ) ⊆ ( × ) )
86 snex { 𝑡 } ∈ V
87 86 58 xpex ( { 𝑡 } × 𝑡 ) ∈ V
88 87 elpw ( ( { 𝑡 } × 𝑡 ) ∈ 𝒫 ( × ) ↔ ( { 𝑡 } × 𝑡 ) ⊆ ( × ) )
89 85 88 sylibr ( 𝑡 → ( { 𝑡 } × 𝑡 ) ∈ 𝒫 ( × ) )
90 eleq1 ( 𝑢 = ( { 𝑡 } × 𝑡 ) → ( 𝑢 ∈ 𝒫 ( × ) ↔ ( { 𝑡 } × 𝑡 ) ∈ 𝒫 ( × ) ) )
91 89 90 syl5ibrcom ( 𝑡 → ( 𝑢 = ( { 𝑡 } × 𝑡 ) → 𝑢 ∈ 𝒫 ( × ) ) )
92 91 rexlimiv ( ∃ 𝑡 𝑢 = ( { 𝑡 } × 𝑡 ) → 𝑢 ∈ 𝒫 ( × ) )
93 92 adantl ( ( 𝑢 ≠ ∅ ∧ ∃ 𝑡 𝑢 = ( { 𝑡 } × 𝑡 ) ) → 𝑢 ∈ 𝒫 ( × ) )
94 93 abssi { 𝑢 ∣ ( 𝑢 ≠ ∅ ∧ ∃ 𝑡 𝑢 = ( { 𝑡 } × 𝑡 ) ) } ⊆ 𝒫 ( × )
95 81 94 ssexi { 𝑢 ∣ ( 𝑢 ≠ ∅ ∧ ∃ 𝑡 𝑢 = ( { 𝑡 } × 𝑡 ) ) } ∈ V
96 1 95 eqeltri 𝐴 ∈ V
97 raleq ( 𝑥 = 𝐴 → ( ∀ 𝑧𝑥 𝑧 ≠ ∅ ↔ ∀ 𝑧𝐴 𝑧 ≠ ∅ ) )
98 raleq ( 𝑥 = 𝐴 → ( ∀ 𝑤𝑥 ( 𝑧𝑤 → ( 𝑧𝑤 ) = ∅ ) ↔ ∀ 𝑤𝐴 ( 𝑧𝑤 → ( 𝑧𝑤 ) = ∅ ) ) )
99 98 raleqbi1dv ( 𝑥 = 𝐴 → ( ∀ 𝑧𝑥𝑤𝑥 ( 𝑧𝑤 → ( 𝑧𝑤 ) = ∅ ) ↔ ∀ 𝑧𝐴𝑤𝐴 ( 𝑧𝑤 → ( 𝑧𝑤 ) = ∅ ) ) )
100 97 99 anbi12d ( 𝑥 = 𝐴 → ( ( ∀ 𝑧𝑥 𝑧 ≠ ∅ ∧ ∀ 𝑧𝑥𝑤𝑥 ( 𝑧𝑤 → ( 𝑧𝑤 ) = ∅ ) ) ↔ ( ∀ 𝑧𝐴 𝑧 ≠ ∅ ∧ ∀ 𝑧𝐴𝑤𝐴 ( 𝑧𝑤 → ( 𝑧𝑤 ) = ∅ ) ) ) )
101 raleq ( 𝑥 = 𝐴 → ( ∀ 𝑧𝑥 ∃! 𝑣 𝑣 ∈ ( 𝑧𝑦 ) ↔ ∀ 𝑧𝐴 ∃! 𝑣 𝑣 ∈ ( 𝑧𝑦 ) ) )
102 101 exbidv ( 𝑥 = 𝐴 → ( ∃ 𝑦𝑧𝑥 ∃! 𝑣 𝑣 ∈ ( 𝑧𝑦 ) ↔ ∃ 𝑦𝑧𝐴 ∃! 𝑣 𝑣 ∈ ( 𝑧𝑦 ) ) )
103 100 102 imbi12d ( 𝑥 = 𝐴 → ( ( ( ∀ 𝑧𝑥 𝑧 ≠ ∅ ∧ ∀ 𝑧𝑥𝑤𝑥 ( 𝑧𝑤 → ( 𝑧𝑤 ) = ∅ ) ) → ∃ 𝑦𝑧𝑥 ∃! 𝑣 𝑣 ∈ ( 𝑧𝑦 ) ) ↔ ( ( ∀ 𝑧𝐴 𝑧 ≠ ∅ ∧ ∀ 𝑧𝐴𝑤𝐴 ( 𝑧𝑤 → ( 𝑧𝑤 ) = ∅ ) ) → ∃ 𝑦𝑧𝐴 ∃! 𝑣 𝑣 ∈ ( 𝑧𝑦 ) ) ) )
104 96 103 spcv ( ∀ 𝑥 ( ( ∀ 𝑧𝑥 𝑧 ≠ ∅ ∧ ∀ 𝑧𝑥𝑤𝑥 ( 𝑧𝑤 → ( 𝑧𝑤 ) = ∅ ) ) → ∃ 𝑦𝑧𝑥 ∃! 𝑣 𝑣 ∈ ( 𝑧𝑦 ) ) → ( ( ∀ 𝑧𝐴 𝑧 ≠ ∅ ∧ ∀ 𝑧𝐴𝑤𝐴 ( 𝑧𝑤 → ( 𝑧𝑤 ) = ∅ ) ) → ∃ 𝑦𝑧𝐴 ∃! 𝑣 𝑣 ∈ ( 𝑧𝑦 ) ) )
105 3 104 sylbi ( 𝜑 → ( ( ∀ 𝑧𝐴 𝑧 ≠ ∅ ∧ ∀ 𝑧𝐴𝑤𝐴 ( 𝑧𝑤 → ( 𝑧𝑤 ) = ∅ ) ) → ∃ 𝑦𝑧𝐴 ∃! 𝑣 𝑣 ∈ ( 𝑧𝑦 ) ) )
106 12 77 105 mp2ani ( 𝜑 → ∃ 𝑦𝑧𝐴 ∃! 𝑣 𝑣 ∈ ( 𝑧𝑦 ) )