Metamath Proof Explorer


Theorem fpr3g

Description: Functions defined by well-founded recursion over a partial order are identical up to relation, domain, and characteristic function. This version of frr3g does not require infinity. (Contributed by Scott Fenton, 24-Aug-2022)

Ref Expression
Assertion fpr3g ( ( ( 𝑅 Fr 𝐴𝑅 Po 𝐴𝑅 Se 𝐴 ) ∧ ( 𝐹 Fn 𝐴 ∧ ∀ 𝑦𝐴 ( 𝐹𝑦 ) = ( 𝑦 𝐻 ( 𝐹 ↾ Pred ( 𝑅 , 𝐴 , 𝑦 ) ) ) ) ∧ ( 𝐺 Fn 𝐴 ∧ ∀ 𝑦𝐴 ( 𝐺𝑦 ) = ( 𝑦 𝐻 ( 𝐺 ↾ Pred ( 𝑅 , 𝐴 , 𝑦 ) ) ) ) ) → 𝐹 = 𝐺 )

Proof

Step Hyp Ref Expression
1 eqidd ( ( ( 𝑅 Fr 𝐴𝑅 Po 𝐴𝑅 Se 𝐴 ) ∧ ( 𝐹 Fn 𝐴 ∧ ∀ 𝑦𝐴 ( 𝐹𝑦 ) = ( 𝑦 𝐻 ( 𝐹 ↾ Pred ( 𝑅 , 𝐴 , 𝑦 ) ) ) ) ∧ ( 𝐺 Fn 𝐴 ∧ ∀ 𝑦𝐴 ( 𝐺𝑦 ) = ( 𝑦 𝐻 ( 𝐺 ↾ Pred ( 𝑅 , 𝐴 , 𝑦 ) ) ) ) ) → 𝐴 = 𝐴 )
2 r19.21v ( ∀ 𝑤 ∈ Pred ( 𝑅 , 𝐴 , 𝑧 ) ( ( ( 𝐹 Fn 𝐴 ∧ ∀ 𝑦𝐴 ( 𝐹𝑦 ) = ( 𝑦 𝐻 ( 𝐹 ↾ Pred ( 𝑅 , 𝐴 , 𝑦 ) ) ) ) ∧ ( 𝐺 Fn 𝐴 ∧ ∀ 𝑦𝐴 ( 𝐺𝑦 ) = ( 𝑦 𝐻 ( 𝐺 ↾ Pred ( 𝑅 , 𝐴 , 𝑦 ) ) ) ) ) → ( 𝐹𝑤 ) = ( 𝐺𝑤 ) ) ↔ ( ( ( 𝐹 Fn 𝐴 ∧ ∀ 𝑦𝐴 ( 𝐹𝑦 ) = ( 𝑦 𝐻 ( 𝐹 ↾ Pred ( 𝑅 , 𝐴 , 𝑦 ) ) ) ) ∧ ( 𝐺 Fn 𝐴 ∧ ∀ 𝑦𝐴 ( 𝐺𝑦 ) = ( 𝑦 𝐻 ( 𝐺 ↾ Pred ( 𝑅 , 𝐴 , 𝑦 ) ) ) ) ) → ∀ 𝑤 ∈ Pred ( 𝑅 , 𝐴 , 𝑧 ) ( 𝐹𝑤 ) = ( 𝐺𝑤 ) ) )
3 simprll ( ( 𝑧𝐴 ∧ ( ( 𝐹 Fn 𝐴 ∧ ∀ 𝑦𝐴 ( 𝐹𝑦 ) = ( 𝑦 𝐻 ( 𝐹 ↾ Pred ( 𝑅 , 𝐴 , 𝑦 ) ) ) ) ∧ ( 𝐺 Fn 𝐴 ∧ ∀ 𝑦𝐴 ( 𝐺𝑦 ) = ( 𝑦 𝐻 ( 𝐺 ↾ Pred ( 𝑅 , 𝐴 , 𝑦 ) ) ) ) ) ) → 𝐹 Fn 𝐴 )
4 simprrl ( ( 𝑧𝐴 ∧ ( ( 𝐹 Fn 𝐴 ∧ ∀ 𝑦𝐴 ( 𝐹𝑦 ) = ( 𝑦 𝐻 ( 𝐹 ↾ Pred ( 𝑅 , 𝐴 , 𝑦 ) ) ) ) ∧ ( 𝐺 Fn 𝐴 ∧ ∀ 𝑦𝐴 ( 𝐺𝑦 ) = ( 𝑦 𝐻 ( 𝐺 ↾ Pred ( 𝑅 , 𝐴 , 𝑦 ) ) ) ) ) ) → 𝐺 Fn 𝐴 )
5 predss Pred ( 𝑅 , 𝐴 , 𝑧 ) ⊆ 𝐴
6 fvreseq ( ( ( 𝐹 Fn 𝐴𝐺 Fn 𝐴 ) ∧ Pred ( 𝑅 , 𝐴 , 𝑧 ) ⊆ 𝐴 ) → ( ( 𝐹 ↾ Pred ( 𝑅 , 𝐴 , 𝑧 ) ) = ( 𝐺 ↾ Pred ( 𝑅 , 𝐴 , 𝑧 ) ) ↔ ∀ 𝑤 ∈ Pred ( 𝑅 , 𝐴 , 𝑧 ) ( 𝐹𝑤 ) = ( 𝐺𝑤 ) ) )
7 5 6 mpan2 ( ( 𝐹 Fn 𝐴𝐺 Fn 𝐴 ) → ( ( 𝐹 ↾ Pred ( 𝑅 , 𝐴 , 𝑧 ) ) = ( 𝐺 ↾ Pred ( 𝑅 , 𝐴 , 𝑧 ) ) ↔ ∀ 𝑤 ∈ Pred ( 𝑅 , 𝐴 , 𝑧 ) ( 𝐹𝑤 ) = ( 𝐺𝑤 ) ) )
8 3 4 7 syl2anc ( ( 𝑧𝐴 ∧ ( ( 𝐹 Fn 𝐴 ∧ ∀ 𝑦𝐴 ( 𝐹𝑦 ) = ( 𝑦 𝐻 ( 𝐹 ↾ Pred ( 𝑅 , 𝐴 , 𝑦 ) ) ) ) ∧ ( 𝐺 Fn 𝐴 ∧ ∀ 𝑦𝐴 ( 𝐺𝑦 ) = ( 𝑦 𝐻 ( 𝐺 ↾ Pred ( 𝑅 , 𝐴 , 𝑦 ) ) ) ) ) ) → ( ( 𝐹 ↾ Pred ( 𝑅 , 𝐴 , 𝑧 ) ) = ( 𝐺 ↾ Pred ( 𝑅 , 𝐴 , 𝑧 ) ) ↔ ∀ 𝑤 ∈ Pred ( 𝑅 , 𝐴 , 𝑧 ) ( 𝐹𝑤 ) = ( 𝐺𝑤 ) ) )
9 8 biimp3ar ( ( 𝑧𝐴 ∧ ( ( 𝐹 Fn 𝐴 ∧ ∀ 𝑦𝐴 ( 𝐹𝑦 ) = ( 𝑦 𝐻 ( 𝐹 ↾ Pred ( 𝑅 , 𝐴 , 𝑦 ) ) ) ) ∧ ( 𝐺 Fn 𝐴 ∧ ∀ 𝑦𝐴 ( 𝐺𝑦 ) = ( 𝑦 𝐻 ( 𝐺 ↾ Pred ( 𝑅 , 𝐴 , 𝑦 ) ) ) ) ) ∧ ∀ 𝑤 ∈ Pred ( 𝑅 , 𝐴 , 𝑧 ) ( 𝐹𝑤 ) = ( 𝐺𝑤 ) ) → ( 𝐹 ↾ Pred ( 𝑅 , 𝐴 , 𝑧 ) ) = ( 𝐺 ↾ Pred ( 𝑅 , 𝐴 , 𝑧 ) ) )
10 9 oveq2d ( ( 𝑧𝐴 ∧ ( ( 𝐹 Fn 𝐴 ∧ ∀ 𝑦𝐴 ( 𝐹𝑦 ) = ( 𝑦 𝐻 ( 𝐹 ↾ Pred ( 𝑅 , 𝐴 , 𝑦 ) ) ) ) ∧ ( 𝐺 Fn 𝐴 ∧ ∀ 𝑦𝐴 ( 𝐺𝑦 ) = ( 𝑦 𝐻 ( 𝐺 ↾ Pred ( 𝑅 , 𝐴 , 𝑦 ) ) ) ) ) ∧ ∀ 𝑤 ∈ Pred ( 𝑅 , 𝐴 , 𝑧 ) ( 𝐹𝑤 ) = ( 𝐺𝑤 ) ) → ( 𝑧 𝐻 ( 𝐹 ↾ Pred ( 𝑅 , 𝐴 , 𝑧 ) ) ) = ( 𝑧 𝐻 ( 𝐺 ↾ Pred ( 𝑅 , 𝐴 , 𝑧 ) ) ) )
11 fveq2 ( 𝑦 = 𝑧 → ( 𝐹𝑦 ) = ( 𝐹𝑧 ) )
12 id ( 𝑦 = 𝑧𝑦 = 𝑧 )
13 predeq3 ( 𝑦 = 𝑧 → Pred ( 𝑅 , 𝐴 , 𝑦 ) = Pred ( 𝑅 , 𝐴 , 𝑧 ) )
14 13 reseq2d ( 𝑦 = 𝑧 → ( 𝐹 ↾ Pred ( 𝑅 , 𝐴 , 𝑦 ) ) = ( 𝐹 ↾ Pred ( 𝑅 , 𝐴 , 𝑧 ) ) )
15 12 14 oveq12d ( 𝑦 = 𝑧 → ( 𝑦 𝐻 ( 𝐹 ↾ Pred ( 𝑅 , 𝐴 , 𝑦 ) ) ) = ( 𝑧 𝐻 ( 𝐹 ↾ Pred ( 𝑅 , 𝐴 , 𝑧 ) ) ) )
16 11 15 eqeq12d ( 𝑦 = 𝑧 → ( ( 𝐹𝑦 ) = ( 𝑦 𝐻 ( 𝐹 ↾ Pred ( 𝑅 , 𝐴 , 𝑦 ) ) ) ↔ ( 𝐹𝑧 ) = ( 𝑧 𝐻 ( 𝐹 ↾ Pred ( 𝑅 , 𝐴 , 𝑧 ) ) ) ) )
17 simp2lr ( ( 𝑧𝐴 ∧ ( ( 𝐹 Fn 𝐴 ∧ ∀ 𝑦𝐴 ( 𝐹𝑦 ) = ( 𝑦 𝐻 ( 𝐹 ↾ Pred ( 𝑅 , 𝐴 , 𝑦 ) ) ) ) ∧ ( 𝐺 Fn 𝐴 ∧ ∀ 𝑦𝐴 ( 𝐺𝑦 ) = ( 𝑦 𝐻 ( 𝐺 ↾ Pred ( 𝑅 , 𝐴 , 𝑦 ) ) ) ) ) ∧ ∀ 𝑤 ∈ Pred ( 𝑅 , 𝐴 , 𝑧 ) ( 𝐹𝑤 ) = ( 𝐺𝑤 ) ) → ∀ 𝑦𝐴 ( 𝐹𝑦 ) = ( 𝑦 𝐻 ( 𝐹 ↾ Pred ( 𝑅 , 𝐴 , 𝑦 ) ) ) )
18 simp1 ( ( 𝑧𝐴 ∧ ( ( 𝐹 Fn 𝐴 ∧ ∀ 𝑦𝐴 ( 𝐹𝑦 ) = ( 𝑦 𝐻 ( 𝐹 ↾ Pred ( 𝑅 , 𝐴 , 𝑦 ) ) ) ) ∧ ( 𝐺 Fn 𝐴 ∧ ∀ 𝑦𝐴 ( 𝐺𝑦 ) = ( 𝑦 𝐻 ( 𝐺 ↾ Pred ( 𝑅 , 𝐴 , 𝑦 ) ) ) ) ) ∧ ∀ 𝑤 ∈ Pred ( 𝑅 , 𝐴 , 𝑧 ) ( 𝐹𝑤 ) = ( 𝐺𝑤 ) ) → 𝑧𝐴 )
19 16 17 18 rspcdva ( ( 𝑧𝐴 ∧ ( ( 𝐹 Fn 𝐴 ∧ ∀ 𝑦𝐴 ( 𝐹𝑦 ) = ( 𝑦 𝐻 ( 𝐹 ↾ Pred ( 𝑅 , 𝐴 , 𝑦 ) ) ) ) ∧ ( 𝐺 Fn 𝐴 ∧ ∀ 𝑦𝐴 ( 𝐺𝑦 ) = ( 𝑦 𝐻 ( 𝐺 ↾ Pred ( 𝑅 , 𝐴 , 𝑦 ) ) ) ) ) ∧ ∀ 𝑤 ∈ Pred ( 𝑅 , 𝐴 , 𝑧 ) ( 𝐹𝑤 ) = ( 𝐺𝑤 ) ) → ( 𝐹𝑧 ) = ( 𝑧 𝐻 ( 𝐹 ↾ Pred ( 𝑅 , 𝐴 , 𝑧 ) ) ) )
20 fveq2 ( 𝑦 = 𝑧 → ( 𝐺𝑦 ) = ( 𝐺𝑧 ) )
21 13 reseq2d ( 𝑦 = 𝑧 → ( 𝐺 ↾ Pred ( 𝑅 , 𝐴 , 𝑦 ) ) = ( 𝐺 ↾ Pred ( 𝑅 , 𝐴 , 𝑧 ) ) )
22 12 21 oveq12d ( 𝑦 = 𝑧 → ( 𝑦 𝐻 ( 𝐺 ↾ Pred ( 𝑅 , 𝐴 , 𝑦 ) ) ) = ( 𝑧 𝐻 ( 𝐺 ↾ Pred ( 𝑅 , 𝐴 , 𝑧 ) ) ) )
23 20 22 eqeq12d ( 𝑦 = 𝑧 → ( ( 𝐺𝑦 ) = ( 𝑦 𝐻 ( 𝐺 ↾ Pred ( 𝑅 , 𝐴 , 𝑦 ) ) ) ↔ ( 𝐺𝑧 ) = ( 𝑧 𝐻 ( 𝐺 ↾ Pred ( 𝑅 , 𝐴 , 𝑧 ) ) ) ) )
24 simp2rr ( ( 𝑧𝐴 ∧ ( ( 𝐹 Fn 𝐴 ∧ ∀ 𝑦𝐴 ( 𝐹𝑦 ) = ( 𝑦 𝐻 ( 𝐹 ↾ Pred ( 𝑅 , 𝐴 , 𝑦 ) ) ) ) ∧ ( 𝐺 Fn 𝐴 ∧ ∀ 𝑦𝐴 ( 𝐺𝑦 ) = ( 𝑦 𝐻 ( 𝐺 ↾ Pred ( 𝑅 , 𝐴 , 𝑦 ) ) ) ) ) ∧ ∀ 𝑤 ∈ Pred ( 𝑅 , 𝐴 , 𝑧 ) ( 𝐹𝑤 ) = ( 𝐺𝑤 ) ) → ∀ 𝑦𝐴 ( 𝐺𝑦 ) = ( 𝑦 𝐻 ( 𝐺 ↾ Pred ( 𝑅 , 𝐴 , 𝑦 ) ) ) )
25 23 24 18 rspcdva ( ( 𝑧𝐴 ∧ ( ( 𝐹 Fn 𝐴 ∧ ∀ 𝑦𝐴 ( 𝐹𝑦 ) = ( 𝑦 𝐻 ( 𝐹 ↾ Pred ( 𝑅 , 𝐴 , 𝑦 ) ) ) ) ∧ ( 𝐺 Fn 𝐴 ∧ ∀ 𝑦𝐴 ( 𝐺𝑦 ) = ( 𝑦 𝐻 ( 𝐺 ↾ Pred ( 𝑅 , 𝐴 , 𝑦 ) ) ) ) ) ∧ ∀ 𝑤 ∈ Pred ( 𝑅 , 𝐴 , 𝑧 ) ( 𝐹𝑤 ) = ( 𝐺𝑤 ) ) → ( 𝐺𝑧 ) = ( 𝑧 𝐻 ( 𝐺 ↾ Pred ( 𝑅 , 𝐴 , 𝑧 ) ) ) )
26 10 19 25 3eqtr4d ( ( 𝑧𝐴 ∧ ( ( 𝐹 Fn 𝐴 ∧ ∀ 𝑦𝐴 ( 𝐹𝑦 ) = ( 𝑦 𝐻 ( 𝐹 ↾ Pred ( 𝑅 , 𝐴 , 𝑦 ) ) ) ) ∧ ( 𝐺 Fn 𝐴 ∧ ∀ 𝑦𝐴 ( 𝐺𝑦 ) = ( 𝑦 𝐻 ( 𝐺 ↾ Pred ( 𝑅 , 𝐴 , 𝑦 ) ) ) ) ) ∧ ∀ 𝑤 ∈ Pred ( 𝑅 , 𝐴 , 𝑧 ) ( 𝐹𝑤 ) = ( 𝐺𝑤 ) ) → ( 𝐹𝑧 ) = ( 𝐺𝑧 ) )
27 26 3exp ( 𝑧𝐴 → ( ( ( 𝐹 Fn 𝐴 ∧ ∀ 𝑦𝐴 ( 𝐹𝑦 ) = ( 𝑦 𝐻 ( 𝐹 ↾ Pred ( 𝑅 , 𝐴 , 𝑦 ) ) ) ) ∧ ( 𝐺 Fn 𝐴 ∧ ∀ 𝑦𝐴 ( 𝐺𝑦 ) = ( 𝑦 𝐻 ( 𝐺 ↾ Pred ( 𝑅 , 𝐴 , 𝑦 ) ) ) ) ) → ( ∀ 𝑤 ∈ Pred ( 𝑅 , 𝐴 , 𝑧 ) ( 𝐹𝑤 ) = ( 𝐺𝑤 ) → ( 𝐹𝑧 ) = ( 𝐺𝑧 ) ) ) )
28 27 a2d ( 𝑧𝐴 → ( ( ( ( 𝐹 Fn 𝐴 ∧ ∀ 𝑦𝐴 ( 𝐹𝑦 ) = ( 𝑦 𝐻 ( 𝐹 ↾ Pred ( 𝑅 , 𝐴 , 𝑦 ) ) ) ) ∧ ( 𝐺 Fn 𝐴 ∧ ∀ 𝑦𝐴 ( 𝐺𝑦 ) = ( 𝑦 𝐻 ( 𝐺 ↾ Pred ( 𝑅 , 𝐴 , 𝑦 ) ) ) ) ) → ∀ 𝑤 ∈ Pred ( 𝑅 , 𝐴 , 𝑧 ) ( 𝐹𝑤 ) = ( 𝐺𝑤 ) ) → ( ( ( 𝐹 Fn 𝐴 ∧ ∀ 𝑦𝐴 ( 𝐹𝑦 ) = ( 𝑦 𝐻 ( 𝐹 ↾ Pred ( 𝑅 , 𝐴 , 𝑦 ) ) ) ) ∧ ( 𝐺 Fn 𝐴 ∧ ∀ 𝑦𝐴 ( 𝐺𝑦 ) = ( 𝑦 𝐻 ( 𝐺 ↾ Pred ( 𝑅 , 𝐴 , 𝑦 ) ) ) ) ) → ( 𝐹𝑧 ) = ( 𝐺𝑧 ) ) ) )
29 2 28 syl5bi ( 𝑧𝐴 → ( ∀ 𝑤 ∈ Pred ( 𝑅 , 𝐴 , 𝑧 ) ( ( ( 𝐹 Fn 𝐴 ∧ ∀ 𝑦𝐴 ( 𝐹𝑦 ) = ( 𝑦 𝐻 ( 𝐹 ↾ Pred ( 𝑅 , 𝐴 , 𝑦 ) ) ) ) ∧ ( 𝐺 Fn 𝐴 ∧ ∀ 𝑦𝐴 ( 𝐺𝑦 ) = ( 𝑦 𝐻 ( 𝐺 ↾ Pred ( 𝑅 , 𝐴 , 𝑦 ) ) ) ) ) → ( 𝐹𝑤 ) = ( 𝐺𝑤 ) ) → ( ( ( 𝐹 Fn 𝐴 ∧ ∀ 𝑦𝐴 ( 𝐹𝑦 ) = ( 𝑦 𝐻 ( 𝐹 ↾ Pred ( 𝑅 , 𝐴 , 𝑦 ) ) ) ) ∧ ( 𝐺 Fn 𝐴 ∧ ∀ 𝑦𝐴 ( 𝐺𝑦 ) = ( 𝑦 𝐻 ( 𝐺 ↾ Pred ( 𝑅 , 𝐴 , 𝑦 ) ) ) ) ) → ( 𝐹𝑧 ) = ( 𝐺𝑧 ) ) ) )
30 fveq2 ( 𝑧 = 𝑤 → ( 𝐹𝑧 ) = ( 𝐹𝑤 ) )
31 fveq2 ( 𝑧 = 𝑤 → ( 𝐺𝑧 ) = ( 𝐺𝑤 ) )
32 30 31 eqeq12d ( 𝑧 = 𝑤 → ( ( 𝐹𝑧 ) = ( 𝐺𝑧 ) ↔ ( 𝐹𝑤 ) = ( 𝐺𝑤 ) ) )
33 32 imbi2d ( 𝑧 = 𝑤 → ( ( ( ( 𝐹 Fn 𝐴 ∧ ∀ 𝑦𝐴 ( 𝐹𝑦 ) = ( 𝑦 𝐻 ( 𝐹 ↾ Pred ( 𝑅 , 𝐴 , 𝑦 ) ) ) ) ∧ ( 𝐺 Fn 𝐴 ∧ ∀ 𝑦𝐴 ( 𝐺𝑦 ) = ( 𝑦 𝐻 ( 𝐺 ↾ Pred ( 𝑅 , 𝐴 , 𝑦 ) ) ) ) ) → ( 𝐹𝑧 ) = ( 𝐺𝑧 ) ) ↔ ( ( ( 𝐹 Fn 𝐴 ∧ ∀ 𝑦𝐴 ( 𝐹𝑦 ) = ( 𝑦 𝐻 ( 𝐹 ↾ Pred ( 𝑅 , 𝐴 , 𝑦 ) ) ) ) ∧ ( 𝐺 Fn 𝐴 ∧ ∀ 𝑦𝐴 ( 𝐺𝑦 ) = ( 𝑦 𝐻 ( 𝐺 ↾ Pred ( 𝑅 , 𝐴 , 𝑦 ) ) ) ) ) → ( 𝐹𝑤 ) = ( 𝐺𝑤 ) ) ) )
34 29 33 frpoins2g ( ( 𝑅 Fr 𝐴𝑅 Po 𝐴𝑅 Se 𝐴 ) → ∀ 𝑧𝐴 ( ( ( 𝐹 Fn 𝐴 ∧ ∀ 𝑦𝐴 ( 𝐹𝑦 ) = ( 𝑦 𝐻 ( 𝐹 ↾ Pred ( 𝑅 , 𝐴 , 𝑦 ) ) ) ) ∧ ( 𝐺 Fn 𝐴 ∧ ∀ 𝑦𝐴 ( 𝐺𝑦 ) = ( 𝑦 𝐻 ( 𝐺 ↾ Pred ( 𝑅 , 𝐴 , 𝑦 ) ) ) ) ) → ( 𝐹𝑧 ) = ( 𝐺𝑧 ) ) )
35 r19.21v ( ∀ 𝑧𝐴 ( ( ( 𝐹 Fn 𝐴 ∧ ∀ 𝑦𝐴 ( 𝐹𝑦 ) = ( 𝑦 𝐻 ( 𝐹 ↾ Pred ( 𝑅 , 𝐴 , 𝑦 ) ) ) ) ∧ ( 𝐺 Fn 𝐴 ∧ ∀ 𝑦𝐴 ( 𝐺𝑦 ) = ( 𝑦 𝐻 ( 𝐺 ↾ Pred ( 𝑅 , 𝐴 , 𝑦 ) ) ) ) ) → ( 𝐹𝑧 ) = ( 𝐺𝑧 ) ) ↔ ( ( ( 𝐹 Fn 𝐴 ∧ ∀ 𝑦𝐴 ( 𝐹𝑦 ) = ( 𝑦 𝐻 ( 𝐹 ↾ Pred ( 𝑅 , 𝐴 , 𝑦 ) ) ) ) ∧ ( 𝐺 Fn 𝐴 ∧ ∀ 𝑦𝐴 ( 𝐺𝑦 ) = ( 𝑦 𝐻 ( 𝐺 ↾ Pred ( 𝑅 , 𝐴 , 𝑦 ) ) ) ) ) → ∀ 𝑧𝐴 ( 𝐹𝑧 ) = ( 𝐺𝑧 ) ) )
36 34 35 sylib ( ( 𝑅 Fr 𝐴𝑅 Po 𝐴𝑅 Se 𝐴 ) → ( ( ( 𝐹 Fn 𝐴 ∧ ∀ 𝑦𝐴 ( 𝐹𝑦 ) = ( 𝑦 𝐻 ( 𝐹 ↾ Pred ( 𝑅 , 𝐴 , 𝑦 ) ) ) ) ∧ ( 𝐺 Fn 𝐴 ∧ ∀ 𝑦𝐴 ( 𝐺𝑦 ) = ( 𝑦 𝐻 ( 𝐺 ↾ Pred ( 𝑅 , 𝐴 , 𝑦 ) ) ) ) ) → ∀ 𝑧𝐴 ( 𝐹𝑧 ) = ( 𝐺𝑧 ) ) )
37 36 3impib ( ( ( 𝑅 Fr 𝐴𝑅 Po 𝐴𝑅 Se 𝐴 ) ∧ ( 𝐹 Fn 𝐴 ∧ ∀ 𝑦𝐴 ( 𝐹𝑦 ) = ( 𝑦 𝐻 ( 𝐹 ↾ Pred ( 𝑅 , 𝐴 , 𝑦 ) ) ) ) ∧ ( 𝐺 Fn 𝐴 ∧ ∀ 𝑦𝐴 ( 𝐺𝑦 ) = ( 𝑦 𝐻 ( 𝐺 ↾ Pred ( 𝑅 , 𝐴 , 𝑦 ) ) ) ) ) → ∀ 𝑧𝐴 ( 𝐹𝑧 ) = ( 𝐺𝑧 ) )
38 simp2l ( ( ( 𝑅 Fr 𝐴𝑅 Po 𝐴𝑅 Se 𝐴 ) ∧ ( 𝐹 Fn 𝐴 ∧ ∀ 𝑦𝐴 ( 𝐹𝑦 ) = ( 𝑦 𝐻 ( 𝐹 ↾ Pred ( 𝑅 , 𝐴 , 𝑦 ) ) ) ) ∧ ( 𝐺 Fn 𝐴 ∧ ∀ 𝑦𝐴 ( 𝐺𝑦 ) = ( 𝑦 𝐻 ( 𝐺 ↾ Pred ( 𝑅 , 𝐴 , 𝑦 ) ) ) ) ) → 𝐹 Fn 𝐴 )
39 simp3l ( ( ( 𝑅 Fr 𝐴𝑅 Po 𝐴𝑅 Se 𝐴 ) ∧ ( 𝐹 Fn 𝐴 ∧ ∀ 𝑦𝐴 ( 𝐹𝑦 ) = ( 𝑦 𝐻 ( 𝐹 ↾ Pred ( 𝑅 , 𝐴 , 𝑦 ) ) ) ) ∧ ( 𝐺 Fn 𝐴 ∧ ∀ 𝑦𝐴 ( 𝐺𝑦 ) = ( 𝑦 𝐻 ( 𝐺 ↾ Pred ( 𝑅 , 𝐴 , 𝑦 ) ) ) ) ) → 𝐺 Fn 𝐴 )
40 eqfnfv2 ( ( 𝐹 Fn 𝐴𝐺 Fn 𝐴 ) → ( 𝐹 = 𝐺 ↔ ( 𝐴 = 𝐴 ∧ ∀ 𝑧𝐴 ( 𝐹𝑧 ) = ( 𝐺𝑧 ) ) ) )
41 38 39 40 syl2anc ( ( ( 𝑅 Fr 𝐴𝑅 Po 𝐴𝑅 Se 𝐴 ) ∧ ( 𝐹 Fn 𝐴 ∧ ∀ 𝑦𝐴 ( 𝐹𝑦 ) = ( 𝑦 𝐻 ( 𝐹 ↾ Pred ( 𝑅 , 𝐴 , 𝑦 ) ) ) ) ∧ ( 𝐺 Fn 𝐴 ∧ ∀ 𝑦𝐴 ( 𝐺𝑦 ) = ( 𝑦 𝐻 ( 𝐺 ↾ Pred ( 𝑅 , 𝐴 , 𝑦 ) ) ) ) ) → ( 𝐹 = 𝐺 ↔ ( 𝐴 = 𝐴 ∧ ∀ 𝑧𝐴 ( 𝐹𝑧 ) = ( 𝐺𝑧 ) ) ) )
42 1 37 41 mpbir2and ( ( ( 𝑅 Fr 𝐴𝑅 Po 𝐴𝑅 Se 𝐴 ) ∧ ( 𝐹 Fn 𝐴 ∧ ∀ 𝑦𝐴 ( 𝐹𝑦 ) = ( 𝑦 𝐻 ( 𝐹 ↾ Pred ( 𝑅 , 𝐴 , 𝑦 ) ) ) ) ∧ ( 𝐺 Fn 𝐴 ∧ ∀ 𝑦𝐴 ( 𝐺𝑦 ) = ( 𝑦 𝐻 ( 𝐺 ↾ Pred ( 𝑅 , 𝐴 , 𝑦 ) ) ) ) ) → 𝐹 = 𝐺 )