Metamath Proof Explorer


Theorem wfrlem12OLD

Description: Lemma for well-ordered recursion. Here, we compute the value of the recursive definition generator. Obsolete as of 18-Nov-2024. (New usage is discouraged.) (Proof modification is discouraged.) (Contributed by Scott Fenton, 21-Apr-2011) (Revised by Mario Carneiro, 26-Jun-2015)

Ref Expression
Hypotheses wfrfunOLD.1 𝑅 We 𝐴
wfrfunOLD.2 𝑅 Se 𝐴
wfrfunOLD.3 𝐹 = wrecs ( 𝑅 , 𝐴 , 𝐺 )
Assertion wfrlem12OLD ( 𝑦 ∈ dom 𝐹 → ( 𝐹𝑦 ) = ( 𝐺 ‘ ( 𝐹 ↾ Pred ( 𝑅 , 𝐴 , 𝑦 ) ) ) )

Proof

Step Hyp Ref Expression
1 wfrfunOLD.1 𝑅 We 𝐴
2 wfrfunOLD.2 𝑅 Se 𝐴
3 wfrfunOLD.3 𝐹 = wrecs ( 𝑅 , 𝐴 , 𝐺 )
4 vex 𝑦 ∈ V
5 4 eldm2 ( 𝑦 ∈ dom 𝐹 ↔ ∃ 𝑧𝑦 , 𝑧 ⟩ ∈ 𝐹 )
6 dfwrecsOLD wrecs ( 𝑅 , 𝐴 , 𝐺 ) = { 𝑓 ∣ ∃ 𝑥 ( 𝑓 Fn 𝑥 ∧ ( 𝑥𝐴 ∧ ∀ 𝑦𝑥 Pred ( 𝑅 , 𝐴 , 𝑦 ) ⊆ 𝑥 ) ∧ ∀ 𝑦𝑥 ( 𝑓𝑦 ) = ( 𝐺 ‘ ( 𝑓 ↾ Pred ( 𝑅 , 𝐴 , 𝑦 ) ) ) ) }
7 3 6 eqtri 𝐹 = { 𝑓 ∣ ∃ 𝑥 ( 𝑓 Fn 𝑥 ∧ ( 𝑥𝐴 ∧ ∀ 𝑦𝑥 Pred ( 𝑅 , 𝐴 , 𝑦 ) ⊆ 𝑥 ) ∧ ∀ 𝑦𝑥 ( 𝑓𝑦 ) = ( 𝐺 ‘ ( 𝑓 ↾ Pred ( 𝑅 , 𝐴 , 𝑦 ) ) ) ) }
8 7 eleq2i ( ⟨ 𝑦 , 𝑧 ⟩ ∈ 𝐹 ↔ ⟨ 𝑦 , 𝑧 ⟩ ∈ { 𝑓 ∣ ∃ 𝑥 ( 𝑓 Fn 𝑥 ∧ ( 𝑥𝐴 ∧ ∀ 𝑦𝑥 Pred ( 𝑅 , 𝐴 , 𝑦 ) ⊆ 𝑥 ) ∧ ∀ 𝑦𝑥 ( 𝑓𝑦 ) = ( 𝐺 ‘ ( 𝑓 ↾ Pred ( 𝑅 , 𝐴 , 𝑦 ) ) ) ) } )
9 eluniab ( ⟨ 𝑦 , 𝑧 ⟩ ∈ { 𝑓 ∣ ∃ 𝑥 ( 𝑓 Fn 𝑥 ∧ ( 𝑥𝐴 ∧ ∀ 𝑦𝑥 Pred ( 𝑅 , 𝐴 , 𝑦 ) ⊆ 𝑥 ) ∧ ∀ 𝑦𝑥 ( 𝑓𝑦 ) = ( 𝐺 ‘ ( 𝑓 ↾ Pred ( 𝑅 , 𝐴 , 𝑦 ) ) ) ) } ↔ ∃ 𝑓 ( ⟨ 𝑦 , 𝑧 ⟩ ∈ 𝑓 ∧ ∃ 𝑥 ( 𝑓 Fn 𝑥 ∧ ( 𝑥𝐴 ∧ ∀ 𝑦𝑥 Pred ( 𝑅 , 𝐴 , 𝑦 ) ⊆ 𝑥 ) ∧ ∀ 𝑦𝑥 ( 𝑓𝑦 ) = ( 𝐺 ‘ ( 𝑓 ↾ Pred ( 𝑅 , 𝐴 , 𝑦 ) ) ) ) ) )
10 8 9 bitri ( ⟨ 𝑦 , 𝑧 ⟩ ∈ 𝐹 ↔ ∃ 𝑓 ( ⟨ 𝑦 , 𝑧 ⟩ ∈ 𝑓 ∧ ∃ 𝑥 ( 𝑓 Fn 𝑥 ∧ ( 𝑥𝐴 ∧ ∀ 𝑦𝑥 Pred ( 𝑅 , 𝐴 , 𝑦 ) ⊆ 𝑥 ) ∧ ∀ 𝑦𝑥 ( 𝑓𝑦 ) = ( 𝐺 ‘ ( 𝑓 ↾ Pred ( 𝑅 , 𝐴 , 𝑦 ) ) ) ) ) )
11 abid ( 𝑓 ∈ { 𝑓 ∣ ∃ 𝑥 ( 𝑓 Fn 𝑥 ∧ ( 𝑥𝐴 ∧ ∀ 𝑦𝑥 Pred ( 𝑅 , 𝐴 , 𝑦 ) ⊆ 𝑥 ) ∧ ∀ 𝑦𝑥 ( 𝑓𝑦 ) = ( 𝐺 ‘ ( 𝑓 ↾ Pred ( 𝑅 , 𝐴 , 𝑦 ) ) ) ) } ↔ ∃ 𝑥 ( 𝑓 Fn 𝑥 ∧ ( 𝑥𝐴 ∧ ∀ 𝑦𝑥 Pred ( 𝑅 , 𝐴 , 𝑦 ) ⊆ 𝑥 ) ∧ ∀ 𝑦𝑥 ( 𝑓𝑦 ) = ( 𝐺 ‘ ( 𝑓 ↾ Pred ( 𝑅 , 𝐴 , 𝑦 ) ) ) ) )
12 elssuni ( 𝑓 ∈ { 𝑓 ∣ ∃ 𝑥 ( 𝑓 Fn 𝑥 ∧ ( 𝑥𝐴 ∧ ∀ 𝑦𝑥 Pred ( 𝑅 , 𝐴 , 𝑦 ) ⊆ 𝑥 ) ∧ ∀ 𝑦𝑥 ( 𝑓𝑦 ) = ( 𝐺 ‘ ( 𝑓 ↾ Pred ( 𝑅 , 𝐴 , 𝑦 ) ) ) ) } → 𝑓 { 𝑓 ∣ ∃ 𝑥 ( 𝑓 Fn 𝑥 ∧ ( 𝑥𝐴 ∧ ∀ 𝑦𝑥 Pred ( 𝑅 , 𝐴 , 𝑦 ) ⊆ 𝑥 ) ∧ ∀ 𝑦𝑥 ( 𝑓𝑦 ) = ( 𝐺 ‘ ( 𝑓 ↾ Pred ( 𝑅 , 𝐴 , 𝑦 ) ) ) ) } )
13 12 7 sseqtrrdi ( 𝑓 ∈ { 𝑓 ∣ ∃ 𝑥 ( 𝑓 Fn 𝑥 ∧ ( 𝑥𝐴 ∧ ∀ 𝑦𝑥 Pred ( 𝑅 , 𝐴 , 𝑦 ) ⊆ 𝑥 ) ∧ ∀ 𝑦𝑥 ( 𝑓𝑦 ) = ( 𝐺 ‘ ( 𝑓 ↾ Pred ( 𝑅 , 𝐴 , 𝑦 ) ) ) ) } → 𝑓𝐹 )
14 11 13 sylbir ( ∃ 𝑥 ( 𝑓 Fn 𝑥 ∧ ( 𝑥𝐴 ∧ ∀ 𝑦𝑥 Pred ( 𝑅 , 𝐴 , 𝑦 ) ⊆ 𝑥 ) ∧ ∀ 𝑦𝑥 ( 𝑓𝑦 ) = ( 𝐺 ‘ ( 𝑓 ↾ Pred ( 𝑅 , 𝐴 , 𝑦 ) ) ) ) → 𝑓𝐹 )
15 fnop ( ( 𝑓 Fn 𝑥 ∧ ⟨ 𝑦 , 𝑧 ⟩ ∈ 𝑓 ) → 𝑦𝑥 )
16 15 ex ( 𝑓 Fn 𝑥 → ( ⟨ 𝑦 , 𝑧 ⟩ ∈ 𝑓𝑦𝑥 ) )
17 rsp ( ∀ 𝑦𝑥 ( 𝑓𝑦 ) = ( 𝐺 ‘ ( 𝑓 ↾ Pred ( 𝑅 , 𝐴 , 𝑦 ) ) ) → ( 𝑦𝑥 → ( 𝑓𝑦 ) = ( 𝐺 ‘ ( 𝑓 ↾ Pred ( 𝑅 , 𝐴 , 𝑦 ) ) ) ) )
18 17 impcom ( ( 𝑦𝑥 ∧ ∀ 𝑦𝑥 ( 𝑓𝑦 ) = ( 𝐺 ‘ ( 𝑓 ↾ Pred ( 𝑅 , 𝐴 , 𝑦 ) ) ) ) → ( 𝑓𝑦 ) = ( 𝐺 ‘ ( 𝑓 ↾ Pred ( 𝑅 , 𝐴 , 𝑦 ) ) ) )
19 rsp ( ∀ 𝑦𝑥 Pred ( 𝑅 , 𝐴 , 𝑦 ) ⊆ 𝑥 → ( 𝑦𝑥 → Pred ( 𝑅 , 𝐴 , 𝑦 ) ⊆ 𝑥 ) )
20 fndm ( 𝑓 Fn 𝑥 → dom 𝑓 = 𝑥 )
21 20 sseq2d ( 𝑓 Fn 𝑥 → ( Pred ( 𝑅 , 𝐴 , 𝑦 ) ⊆ dom 𝑓 ↔ Pred ( 𝑅 , 𝐴 , 𝑦 ) ⊆ 𝑥 ) )
22 20 eleq2d ( 𝑓 Fn 𝑥 → ( 𝑦 ∈ dom 𝑓𝑦𝑥 ) )
23 21 22 anbi12d ( 𝑓 Fn 𝑥 → ( ( Pred ( 𝑅 , 𝐴 , 𝑦 ) ⊆ dom 𝑓𝑦 ∈ dom 𝑓 ) ↔ ( Pred ( 𝑅 , 𝐴 , 𝑦 ) ⊆ 𝑥𝑦𝑥 ) ) )
24 23 biimprd ( 𝑓 Fn 𝑥 → ( ( Pred ( 𝑅 , 𝐴 , 𝑦 ) ⊆ 𝑥𝑦𝑥 ) → ( Pred ( 𝑅 , 𝐴 , 𝑦 ) ⊆ dom 𝑓𝑦 ∈ dom 𝑓 ) ) )
25 24 expd ( 𝑓 Fn 𝑥 → ( Pred ( 𝑅 , 𝐴 , 𝑦 ) ⊆ 𝑥 → ( 𝑦𝑥 → ( Pred ( 𝑅 , 𝐴 , 𝑦 ) ⊆ dom 𝑓𝑦 ∈ dom 𝑓 ) ) ) )
26 25 impcom ( ( Pred ( 𝑅 , 𝐴 , 𝑦 ) ⊆ 𝑥𝑓 Fn 𝑥 ) → ( 𝑦𝑥 → ( Pred ( 𝑅 , 𝐴 , 𝑦 ) ⊆ dom 𝑓𝑦 ∈ dom 𝑓 ) ) )
27 1 2 3 wfrfunOLD Fun 𝐹
28 funssfv ( ( Fun 𝐹𝑓𝐹𝑦 ∈ dom 𝑓 ) → ( 𝐹𝑦 ) = ( 𝑓𝑦 ) )
29 28 3adant3l ( ( Fun 𝐹𝑓𝐹 ∧ ( Pred ( 𝑅 , 𝐴 , 𝑦 ) ⊆ dom 𝑓𝑦 ∈ dom 𝑓 ) ) → ( 𝐹𝑦 ) = ( 𝑓𝑦 ) )
30 fun2ssres ( ( Fun 𝐹𝑓𝐹 ∧ Pred ( 𝑅 , 𝐴 , 𝑦 ) ⊆ dom 𝑓 ) → ( 𝐹 ↾ Pred ( 𝑅 , 𝐴 , 𝑦 ) ) = ( 𝑓 ↾ Pred ( 𝑅 , 𝐴 , 𝑦 ) ) )
31 30 3adant3r ( ( Fun 𝐹𝑓𝐹 ∧ ( Pred ( 𝑅 , 𝐴 , 𝑦 ) ⊆ dom 𝑓𝑦 ∈ dom 𝑓 ) ) → ( 𝐹 ↾ Pred ( 𝑅 , 𝐴 , 𝑦 ) ) = ( 𝑓 ↾ Pred ( 𝑅 , 𝐴 , 𝑦 ) ) )
32 31 fveq2d ( ( Fun 𝐹𝑓𝐹 ∧ ( Pred ( 𝑅 , 𝐴 , 𝑦 ) ⊆ dom 𝑓𝑦 ∈ dom 𝑓 ) ) → ( 𝐺 ‘ ( 𝐹 ↾ Pred ( 𝑅 , 𝐴 , 𝑦 ) ) ) = ( 𝐺 ‘ ( 𝑓 ↾ Pred ( 𝑅 , 𝐴 , 𝑦 ) ) ) )
33 29 32 eqeq12d ( ( Fun 𝐹𝑓𝐹 ∧ ( Pred ( 𝑅 , 𝐴 , 𝑦 ) ⊆ dom 𝑓𝑦 ∈ dom 𝑓 ) ) → ( ( 𝐹𝑦 ) = ( 𝐺 ‘ ( 𝐹 ↾ Pred ( 𝑅 , 𝐴 , 𝑦 ) ) ) ↔ ( 𝑓𝑦 ) = ( 𝐺 ‘ ( 𝑓 ↾ Pred ( 𝑅 , 𝐴 , 𝑦 ) ) ) ) )
34 33 biimprd ( ( Fun 𝐹𝑓𝐹 ∧ ( Pred ( 𝑅 , 𝐴 , 𝑦 ) ⊆ dom 𝑓𝑦 ∈ dom 𝑓 ) ) → ( ( 𝑓𝑦 ) = ( 𝐺 ‘ ( 𝑓 ↾ Pred ( 𝑅 , 𝐴 , 𝑦 ) ) ) → ( 𝐹𝑦 ) = ( 𝐺 ‘ ( 𝐹 ↾ Pred ( 𝑅 , 𝐴 , 𝑦 ) ) ) ) )
35 27 34 mp3an1 ( ( 𝑓𝐹 ∧ ( Pred ( 𝑅 , 𝐴 , 𝑦 ) ⊆ dom 𝑓𝑦 ∈ dom 𝑓 ) ) → ( ( 𝑓𝑦 ) = ( 𝐺 ‘ ( 𝑓 ↾ Pred ( 𝑅 , 𝐴 , 𝑦 ) ) ) → ( 𝐹𝑦 ) = ( 𝐺 ‘ ( 𝐹 ↾ Pred ( 𝑅 , 𝐴 , 𝑦 ) ) ) ) )
36 35 expcom ( ( Pred ( 𝑅 , 𝐴 , 𝑦 ) ⊆ dom 𝑓𝑦 ∈ dom 𝑓 ) → ( 𝑓𝐹 → ( ( 𝑓𝑦 ) = ( 𝐺 ‘ ( 𝑓 ↾ Pred ( 𝑅 , 𝐴 , 𝑦 ) ) ) → ( 𝐹𝑦 ) = ( 𝐺 ‘ ( 𝐹 ↾ Pred ( 𝑅 , 𝐴 , 𝑦 ) ) ) ) ) )
37 36 com23 ( ( Pred ( 𝑅 , 𝐴 , 𝑦 ) ⊆ dom 𝑓𝑦 ∈ dom 𝑓 ) → ( ( 𝑓𝑦 ) = ( 𝐺 ‘ ( 𝑓 ↾ Pred ( 𝑅 , 𝐴 , 𝑦 ) ) ) → ( 𝑓𝐹 → ( 𝐹𝑦 ) = ( 𝐺 ‘ ( 𝐹 ↾ Pred ( 𝑅 , 𝐴 , 𝑦 ) ) ) ) ) )
38 26 37 syl6com ( 𝑦𝑥 → ( ( Pred ( 𝑅 , 𝐴 , 𝑦 ) ⊆ 𝑥𝑓 Fn 𝑥 ) → ( ( 𝑓𝑦 ) = ( 𝐺 ‘ ( 𝑓 ↾ Pred ( 𝑅 , 𝐴 , 𝑦 ) ) ) → ( 𝑓𝐹 → ( 𝐹𝑦 ) = ( 𝐺 ‘ ( 𝐹 ↾ Pred ( 𝑅 , 𝐴 , 𝑦 ) ) ) ) ) ) )
39 38 expd ( 𝑦𝑥 → ( Pred ( 𝑅 , 𝐴 , 𝑦 ) ⊆ 𝑥 → ( 𝑓 Fn 𝑥 → ( ( 𝑓𝑦 ) = ( 𝐺 ‘ ( 𝑓 ↾ Pred ( 𝑅 , 𝐴 , 𝑦 ) ) ) → ( 𝑓𝐹 → ( 𝐹𝑦 ) = ( 𝐺 ‘ ( 𝐹 ↾ Pred ( 𝑅 , 𝐴 , 𝑦 ) ) ) ) ) ) ) )
40 39 com34 ( 𝑦𝑥 → ( Pred ( 𝑅 , 𝐴 , 𝑦 ) ⊆ 𝑥 → ( ( 𝑓𝑦 ) = ( 𝐺 ‘ ( 𝑓 ↾ Pred ( 𝑅 , 𝐴 , 𝑦 ) ) ) → ( 𝑓 Fn 𝑥 → ( 𝑓𝐹 → ( 𝐹𝑦 ) = ( 𝐺 ‘ ( 𝐹 ↾ Pred ( 𝑅 , 𝐴 , 𝑦 ) ) ) ) ) ) ) )
41 19 40 sylcom ( ∀ 𝑦𝑥 Pred ( 𝑅 , 𝐴 , 𝑦 ) ⊆ 𝑥 → ( 𝑦𝑥 → ( ( 𝑓𝑦 ) = ( 𝐺 ‘ ( 𝑓 ↾ Pred ( 𝑅 , 𝐴 , 𝑦 ) ) ) → ( 𝑓 Fn 𝑥 → ( 𝑓𝐹 → ( 𝐹𝑦 ) = ( 𝐺 ‘ ( 𝐹 ↾ Pred ( 𝑅 , 𝐴 , 𝑦 ) ) ) ) ) ) ) )
42 41 adantl ( ( 𝑥𝐴 ∧ ∀ 𝑦𝑥 Pred ( 𝑅 , 𝐴 , 𝑦 ) ⊆ 𝑥 ) → ( 𝑦𝑥 → ( ( 𝑓𝑦 ) = ( 𝐺 ‘ ( 𝑓 ↾ Pred ( 𝑅 , 𝐴 , 𝑦 ) ) ) → ( 𝑓 Fn 𝑥 → ( 𝑓𝐹 → ( 𝐹𝑦 ) = ( 𝐺 ‘ ( 𝐹 ↾ Pred ( 𝑅 , 𝐴 , 𝑦 ) ) ) ) ) ) ) )
43 42 com14 ( 𝑓 Fn 𝑥 → ( 𝑦𝑥 → ( ( 𝑓𝑦 ) = ( 𝐺 ‘ ( 𝑓 ↾ Pred ( 𝑅 , 𝐴 , 𝑦 ) ) ) → ( ( 𝑥𝐴 ∧ ∀ 𝑦𝑥 Pred ( 𝑅 , 𝐴 , 𝑦 ) ⊆ 𝑥 ) → ( 𝑓𝐹 → ( 𝐹𝑦 ) = ( 𝐺 ‘ ( 𝐹 ↾ Pred ( 𝑅 , 𝐴 , 𝑦 ) ) ) ) ) ) ) )
44 18 43 syl7 ( 𝑓 Fn 𝑥 → ( 𝑦𝑥 → ( ( 𝑦𝑥 ∧ ∀ 𝑦𝑥 ( 𝑓𝑦 ) = ( 𝐺 ‘ ( 𝑓 ↾ Pred ( 𝑅 , 𝐴 , 𝑦 ) ) ) ) → ( ( 𝑥𝐴 ∧ ∀ 𝑦𝑥 Pred ( 𝑅 , 𝐴 , 𝑦 ) ⊆ 𝑥 ) → ( 𝑓𝐹 → ( 𝐹𝑦 ) = ( 𝐺 ‘ ( 𝐹 ↾ Pred ( 𝑅 , 𝐴 , 𝑦 ) ) ) ) ) ) ) )
45 44 exp4a ( 𝑓 Fn 𝑥 → ( 𝑦𝑥 → ( 𝑦𝑥 → ( ∀ 𝑦𝑥 ( 𝑓𝑦 ) = ( 𝐺 ‘ ( 𝑓 ↾ Pred ( 𝑅 , 𝐴 , 𝑦 ) ) ) → ( ( 𝑥𝐴 ∧ ∀ 𝑦𝑥 Pred ( 𝑅 , 𝐴 , 𝑦 ) ⊆ 𝑥 ) → ( 𝑓𝐹 → ( 𝐹𝑦 ) = ( 𝐺 ‘ ( 𝐹 ↾ Pred ( 𝑅 , 𝐴 , 𝑦 ) ) ) ) ) ) ) ) )
46 45 pm2.43d ( 𝑓 Fn 𝑥 → ( 𝑦𝑥 → ( ∀ 𝑦𝑥 ( 𝑓𝑦 ) = ( 𝐺 ‘ ( 𝑓 ↾ Pred ( 𝑅 , 𝐴 , 𝑦 ) ) ) → ( ( 𝑥𝐴 ∧ ∀ 𝑦𝑥 Pred ( 𝑅 , 𝐴 , 𝑦 ) ⊆ 𝑥 ) → ( 𝑓𝐹 → ( 𝐹𝑦 ) = ( 𝐺 ‘ ( 𝐹 ↾ Pred ( 𝑅 , 𝐴 , 𝑦 ) ) ) ) ) ) ) )
47 46 com34 ( 𝑓 Fn 𝑥 → ( 𝑦𝑥 → ( ( 𝑥𝐴 ∧ ∀ 𝑦𝑥 Pred ( 𝑅 , 𝐴 , 𝑦 ) ⊆ 𝑥 ) → ( ∀ 𝑦𝑥 ( 𝑓𝑦 ) = ( 𝐺 ‘ ( 𝑓 ↾ Pred ( 𝑅 , 𝐴 , 𝑦 ) ) ) → ( 𝑓𝐹 → ( 𝐹𝑦 ) = ( 𝐺 ‘ ( 𝐹 ↾ Pred ( 𝑅 , 𝐴 , 𝑦 ) ) ) ) ) ) ) )
48 16 47 syldc ( ⟨ 𝑦 , 𝑧 ⟩ ∈ 𝑓 → ( 𝑓 Fn 𝑥 → ( ( 𝑥𝐴 ∧ ∀ 𝑦𝑥 Pred ( 𝑅 , 𝐴 , 𝑦 ) ⊆ 𝑥 ) → ( ∀ 𝑦𝑥 ( 𝑓𝑦 ) = ( 𝐺 ‘ ( 𝑓 ↾ Pred ( 𝑅 , 𝐴 , 𝑦 ) ) ) → ( 𝑓𝐹 → ( 𝐹𝑦 ) = ( 𝐺 ‘ ( 𝐹 ↾ Pred ( 𝑅 , 𝐴 , 𝑦 ) ) ) ) ) ) ) )
49 48 3impd ( ⟨ 𝑦 , 𝑧 ⟩ ∈ 𝑓 → ( ( 𝑓 Fn 𝑥 ∧ ( 𝑥𝐴 ∧ ∀ 𝑦𝑥 Pred ( 𝑅 , 𝐴 , 𝑦 ) ⊆ 𝑥 ) ∧ ∀ 𝑦𝑥 ( 𝑓𝑦 ) = ( 𝐺 ‘ ( 𝑓 ↾ Pred ( 𝑅 , 𝐴 , 𝑦 ) ) ) ) → ( 𝑓𝐹 → ( 𝐹𝑦 ) = ( 𝐺 ‘ ( 𝐹 ↾ Pred ( 𝑅 , 𝐴 , 𝑦 ) ) ) ) ) )
50 49 exlimdv ( ⟨ 𝑦 , 𝑧 ⟩ ∈ 𝑓 → ( ∃ 𝑥 ( 𝑓 Fn 𝑥 ∧ ( 𝑥𝐴 ∧ ∀ 𝑦𝑥 Pred ( 𝑅 , 𝐴 , 𝑦 ) ⊆ 𝑥 ) ∧ ∀ 𝑦𝑥 ( 𝑓𝑦 ) = ( 𝐺 ‘ ( 𝑓 ↾ Pred ( 𝑅 , 𝐴 , 𝑦 ) ) ) ) → ( 𝑓𝐹 → ( 𝐹𝑦 ) = ( 𝐺 ‘ ( 𝐹 ↾ Pred ( 𝑅 , 𝐴 , 𝑦 ) ) ) ) ) )
51 14 50 mpdi ( ⟨ 𝑦 , 𝑧 ⟩ ∈ 𝑓 → ( ∃ 𝑥 ( 𝑓 Fn 𝑥 ∧ ( 𝑥𝐴 ∧ ∀ 𝑦𝑥 Pred ( 𝑅 , 𝐴 , 𝑦 ) ⊆ 𝑥 ) ∧ ∀ 𝑦𝑥 ( 𝑓𝑦 ) = ( 𝐺 ‘ ( 𝑓 ↾ Pred ( 𝑅 , 𝐴 , 𝑦 ) ) ) ) → ( 𝐹𝑦 ) = ( 𝐺 ‘ ( 𝐹 ↾ Pred ( 𝑅 , 𝐴 , 𝑦 ) ) ) ) )
52 51 imp ( ( ⟨ 𝑦 , 𝑧 ⟩ ∈ 𝑓 ∧ ∃ 𝑥 ( 𝑓 Fn 𝑥 ∧ ( 𝑥𝐴 ∧ ∀ 𝑦𝑥 Pred ( 𝑅 , 𝐴 , 𝑦 ) ⊆ 𝑥 ) ∧ ∀ 𝑦𝑥 ( 𝑓𝑦 ) = ( 𝐺 ‘ ( 𝑓 ↾ Pred ( 𝑅 , 𝐴 , 𝑦 ) ) ) ) ) → ( 𝐹𝑦 ) = ( 𝐺 ‘ ( 𝐹 ↾ Pred ( 𝑅 , 𝐴 , 𝑦 ) ) ) )
53 52 exlimiv ( ∃ 𝑓 ( ⟨ 𝑦 , 𝑧 ⟩ ∈ 𝑓 ∧ ∃ 𝑥 ( 𝑓 Fn 𝑥 ∧ ( 𝑥𝐴 ∧ ∀ 𝑦𝑥 Pred ( 𝑅 , 𝐴 , 𝑦 ) ⊆ 𝑥 ) ∧ ∀ 𝑦𝑥 ( 𝑓𝑦 ) = ( 𝐺 ‘ ( 𝑓 ↾ Pred ( 𝑅 , 𝐴 , 𝑦 ) ) ) ) ) → ( 𝐹𝑦 ) = ( 𝐺 ‘ ( 𝐹 ↾ Pred ( 𝑅 , 𝐴 , 𝑦 ) ) ) )
54 10 53 sylbi ( ⟨ 𝑦 , 𝑧 ⟩ ∈ 𝐹 → ( 𝐹𝑦 ) = ( 𝐺 ‘ ( 𝐹 ↾ Pred ( 𝑅 , 𝐴 , 𝑦 ) ) ) )
55 54 exlimiv ( ∃ 𝑧𝑦 , 𝑧 ⟩ ∈ 𝐹 → ( 𝐹𝑦 ) = ( 𝐺 ‘ ( 𝐹 ↾ Pred ( 𝑅 , 𝐴 , 𝑦 ) ) ) )
56 5 55 sylbi ( 𝑦 ∈ dom 𝐹 → ( 𝐹𝑦 ) = ( 𝐺 ‘ ( 𝐹 ↾ Pred ( 𝑅 , 𝐴 , 𝑦 ) ) ) )