Metamath Proof Explorer


Theorem fundcmpsurbijinjpreimafv

Description: Every function F : A --> B can be decomposed into a surjective function onto P , a bijective function from P and an injective function into the codomain of F . (Contributed by AV, 22-Mar-2024)

Ref Expression
Hypothesis fundcmpsurinj.p 𝑃 = { 𝑧 ∣ ∃ 𝑥𝐴 𝑧 = ( 𝐹 “ { ( 𝐹𝑥 ) } ) }
Assertion fundcmpsurbijinjpreimafv ( ( 𝐹 : 𝐴𝐵𝐴𝑉 ) → ∃ 𝑔𝑖 ( ( 𝑔 : 𝐴onto𝑃 : 𝑃1-1-onto→ ( 𝐹𝐴 ) ∧ 𝑖 : ( 𝐹𝐴 ) –1-1𝐵 ) ∧ 𝐹 = ( ( 𝑖 ) ∘ 𝑔 ) ) )

Proof

Step Hyp Ref Expression
1 fundcmpsurinj.p 𝑃 = { 𝑧 ∣ ∃ 𝑥𝐴 𝑧 = ( 𝐹 “ { ( 𝐹𝑥 ) } ) }
2 simpr ( ( 𝐹 : 𝐴𝐵𝐴𝑉 ) → 𝐴𝑉 )
3 2 mptexd ( ( 𝐹 : 𝐴𝐵𝐴𝑉 ) → ( 𝑎𝐴 ↦ ( 𝐹 “ { ( 𝐹𝑎 ) } ) ) ∈ V )
4 1 setpreimafvex ( 𝐴𝑉𝑃 ∈ V )
5 4 adantl ( ( 𝐹 : 𝐴𝐵𝐴𝑉 ) → 𝑃 ∈ V )
6 5 mptexd ( ( 𝐹 : 𝐴𝐵𝐴𝑉 ) → ( 𝑦𝑃 ( 𝐹𝑦 ) ) ∈ V )
7 ffun ( 𝐹 : 𝐴𝐵 → Fun 𝐹 )
8 funimaexg ( ( Fun 𝐹𝐴𝑉 ) → ( 𝐹𝐴 ) ∈ V )
9 7 8 sylan ( ( 𝐹 : 𝐴𝐵𝐴𝑉 ) → ( 𝐹𝐴 ) ∈ V )
10 9 resiexd ( ( 𝐹 : 𝐴𝐵𝐴𝑉 ) → ( I ↾ ( 𝐹𝐴 ) ) ∈ V )
11 3 6 10 3jca ( ( 𝐹 : 𝐴𝐵𝐴𝑉 ) → ( ( 𝑎𝐴 ↦ ( 𝐹 “ { ( 𝐹𝑎 ) } ) ) ∈ V ∧ ( 𝑦𝑃 ( 𝐹𝑦 ) ) ∈ V ∧ ( I ↾ ( 𝐹𝐴 ) ) ∈ V ) )
12 ffn ( 𝐹 : 𝐴𝐵𝐹 Fn 𝐴 )
13 fveq2 ( 𝑎 = 𝑥 → ( 𝐹𝑎 ) = ( 𝐹𝑥 ) )
14 13 sneqd ( 𝑎 = 𝑥 → { ( 𝐹𝑎 ) } = { ( 𝐹𝑥 ) } )
15 14 imaeq2d ( 𝑎 = 𝑥 → ( 𝐹 “ { ( 𝐹𝑎 ) } ) = ( 𝐹 “ { ( 𝐹𝑥 ) } ) )
16 15 cbvmptv ( 𝑎𝐴 ↦ ( 𝐹 “ { ( 𝐹𝑎 ) } ) ) = ( 𝑥𝐴 ↦ ( 𝐹 “ { ( 𝐹𝑥 ) } ) )
17 1 16 fundcmpsurinjlem2 ( ( 𝐹 Fn 𝐴𝐴𝑉 ) → ( 𝑎𝐴 ↦ ( 𝐹 “ { ( 𝐹𝑎 ) } ) ) : 𝐴onto𝑃 )
18 12 17 sylan ( ( 𝐹 : 𝐴𝐵𝐴𝑉 ) → ( 𝑎𝐴 ↦ ( 𝐹 “ { ( 𝐹𝑎 ) } ) ) : 𝐴onto𝑃 )
19 eqid ( 𝑦𝑃 ( 𝐹𝑦 ) ) = ( 𝑦𝑃 ( 𝐹𝑦 ) )
20 1 19 imasetpreimafvbij ( ( 𝐹 Fn 𝐴𝐴𝑉 ) → ( 𝑦𝑃 ( 𝐹𝑦 ) ) : 𝑃1-1-onto→ ( 𝐹𝐴 ) )
21 12 20 sylan ( ( 𝐹 : 𝐴𝐵𝐴𝑉 ) → ( 𝑦𝑃 ( 𝐹𝑦 ) ) : 𝑃1-1-onto→ ( 𝐹𝐴 ) )
22 f1oi ( I ↾ ( 𝐹𝐴 ) ) : ( 𝐹𝐴 ) –1-1-onto→ ( 𝐹𝐴 )
23 f1of1 ( ( I ↾ ( 𝐹𝐴 ) ) : ( 𝐹𝐴 ) –1-1-onto→ ( 𝐹𝐴 ) → ( I ↾ ( 𝐹𝐴 ) ) : ( 𝐹𝐴 ) –1-1→ ( 𝐹𝐴 ) )
24 fimass ( 𝐹 : 𝐴𝐵 → ( 𝐹𝐴 ) ⊆ 𝐵 )
25 f1ss ( ( ( I ↾ ( 𝐹𝐴 ) ) : ( 𝐹𝐴 ) –1-1→ ( 𝐹𝐴 ) ∧ ( 𝐹𝐴 ) ⊆ 𝐵 ) → ( I ↾ ( 𝐹𝐴 ) ) : ( 𝐹𝐴 ) –1-1𝐵 )
26 24 25 sylan2 ( ( ( I ↾ ( 𝐹𝐴 ) ) : ( 𝐹𝐴 ) –1-1→ ( 𝐹𝐴 ) ∧ 𝐹 : 𝐴𝐵 ) → ( I ↾ ( 𝐹𝐴 ) ) : ( 𝐹𝐴 ) –1-1𝐵 )
27 26 ex ( ( I ↾ ( 𝐹𝐴 ) ) : ( 𝐹𝐴 ) –1-1→ ( 𝐹𝐴 ) → ( 𝐹 : 𝐴𝐵 → ( I ↾ ( 𝐹𝐴 ) ) : ( 𝐹𝐴 ) –1-1𝐵 ) )
28 22 23 27 mp2b ( 𝐹 : 𝐴𝐵 → ( I ↾ ( 𝐹𝐴 ) ) : ( 𝐹𝐴 ) –1-1𝐵 )
29 28 adantr ( ( 𝐹 : 𝐴𝐵𝐴𝑉 ) → ( I ↾ ( 𝐹𝐴 ) ) : ( 𝐹𝐴 ) –1-1𝐵 )
30 18 21 29 3jca ( ( 𝐹 : 𝐴𝐵𝐴𝑉 ) → ( ( 𝑎𝐴 ↦ ( 𝐹 “ { ( 𝐹𝑎 ) } ) ) : 𝐴onto𝑃 ∧ ( 𝑦𝑃 ( 𝐹𝑦 ) ) : 𝑃1-1-onto→ ( 𝐹𝐴 ) ∧ ( I ↾ ( 𝐹𝐴 ) ) : ( 𝐹𝐴 ) –1-1𝐵 ) )
31 12 adantr ( ( 𝐹 : 𝐴𝐵𝐴𝑉 ) → 𝐹 Fn 𝐴 )
32 uniimaprimaeqfv ( ( 𝐹 Fn 𝐴𝑎𝐴 ) → ( 𝐹 “ ( 𝐹 “ { ( 𝐹𝑎 ) } ) ) = ( 𝐹𝑎 ) )
33 31 32 sylan ( ( ( 𝐹 : 𝐴𝐵𝐴𝑉 ) ∧ 𝑎𝐴 ) → ( 𝐹 “ ( 𝐹 “ { ( 𝐹𝑎 ) } ) ) = ( 𝐹𝑎 ) )
34 33 fveq2d ( ( ( 𝐹 : 𝐴𝐵𝐴𝑉 ) ∧ 𝑎𝐴 ) → ( ( I ↾ ( 𝐹𝐴 ) ) ‘ ( 𝐹 “ ( 𝐹 “ { ( 𝐹𝑎 ) } ) ) ) = ( ( I ↾ ( 𝐹𝐴 ) ) ‘ ( 𝐹𝑎 ) ) )
35 34 mpteq2dva ( ( 𝐹 : 𝐴𝐵𝐴𝑉 ) → ( 𝑎𝐴 ↦ ( ( I ↾ ( 𝐹𝐴 ) ) ‘ ( 𝐹 “ ( 𝐹 “ { ( 𝐹𝑎 ) } ) ) ) ) = ( 𝑎𝐴 ↦ ( ( I ↾ ( 𝐹𝐴 ) ) ‘ ( 𝐹𝑎 ) ) ) )
36 ffrn ( 𝐹 : 𝐴𝐵𝐹 : 𝐴 ⟶ ran 𝐹 )
37 36 adantr ( ( 𝐹 : 𝐴𝐵𝐴𝑉 ) → 𝐹 : 𝐴 ⟶ ran 𝐹 )
38 37 funfvima2d ( ( ( 𝐹 : 𝐴𝐵𝐴𝑉 ) ∧ 𝑎𝐴 ) → ( 𝐹𝑎 ) ∈ ( 𝐹𝐴 ) )
39 fvresi ( ( 𝐹𝑎 ) ∈ ( 𝐹𝐴 ) → ( ( I ↾ ( 𝐹𝐴 ) ) ‘ ( 𝐹𝑎 ) ) = ( 𝐹𝑎 ) )
40 38 39 syl ( ( ( 𝐹 : 𝐴𝐵𝐴𝑉 ) ∧ 𝑎𝐴 ) → ( ( I ↾ ( 𝐹𝐴 ) ) ‘ ( 𝐹𝑎 ) ) = ( 𝐹𝑎 ) )
41 40 mpteq2dva ( ( 𝐹 : 𝐴𝐵𝐴𝑉 ) → ( 𝑎𝐴 ↦ ( ( I ↾ ( 𝐹𝐴 ) ) ‘ ( 𝐹𝑎 ) ) ) = ( 𝑎𝐴 ↦ ( 𝐹𝑎 ) ) )
42 35 41 eqtrd ( ( 𝐹 : 𝐴𝐵𝐴𝑉 ) → ( 𝑎𝐴 ↦ ( ( I ↾ ( 𝐹𝐴 ) ) ‘ ( 𝐹 “ ( 𝐹 “ { ( 𝐹𝑎 ) } ) ) ) ) = ( 𝑎𝐴 ↦ ( 𝐹𝑎 ) ) )
43 12 ad2antrr ( ( ( 𝐹 : 𝐴𝐵𝐴𝑉 ) ∧ 𝑎𝐴 ) → 𝐹 Fn 𝐴 )
44 2 adantr ( ( ( 𝐹 : 𝐴𝐵𝐴𝑉 ) ∧ 𝑎𝐴 ) → 𝐴𝑉 )
45 simpr ( ( ( 𝐹 : 𝐴𝐵𝐴𝑉 ) ∧ 𝑎𝐴 ) → 𝑎𝐴 )
46 1 preimafvelsetpreimafv ( ( 𝐹 Fn 𝐴𝐴𝑉𝑎𝐴 ) → ( 𝐹 “ { ( 𝐹𝑎 ) } ) ∈ 𝑃 )
47 43 44 45 46 syl3anc ( ( ( 𝐹 : 𝐴𝐵𝐴𝑉 ) ∧ 𝑎𝐴 ) → ( 𝐹 “ { ( 𝐹𝑎 ) } ) ∈ 𝑃 )
48 eqidd ( ( 𝐹 : 𝐴𝐵𝐴𝑉 ) → ( 𝑎𝐴 ↦ ( 𝐹 “ { ( 𝐹𝑎 ) } ) ) = ( 𝑎𝐴 ↦ ( 𝐹 “ { ( 𝐹𝑎 ) } ) ) )
49 eqidd ( ( 𝐹 : 𝐴𝐵𝐴𝑉 ) → ( 𝑦𝑃 ↦ ( ( I ↾ ( 𝐹𝐴 ) ) ‘ ( 𝐹𝑦 ) ) ) = ( 𝑦𝑃 ↦ ( ( I ↾ ( 𝐹𝐴 ) ) ‘ ( 𝐹𝑦 ) ) ) )
50 imaeq2 ( 𝑦 = ( 𝐹 “ { ( 𝐹𝑎 ) } ) → ( 𝐹𝑦 ) = ( 𝐹 “ ( 𝐹 “ { ( 𝐹𝑎 ) } ) ) )
51 50 unieqd ( 𝑦 = ( 𝐹 “ { ( 𝐹𝑎 ) } ) → ( 𝐹𝑦 ) = ( 𝐹 “ ( 𝐹 “ { ( 𝐹𝑎 ) } ) ) )
52 51 fveq2d ( 𝑦 = ( 𝐹 “ { ( 𝐹𝑎 ) } ) → ( ( I ↾ ( 𝐹𝐴 ) ) ‘ ( 𝐹𝑦 ) ) = ( ( I ↾ ( 𝐹𝐴 ) ) ‘ ( 𝐹 “ ( 𝐹 “ { ( 𝐹𝑎 ) } ) ) ) )
53 47 48 49 52 fmptco ( ( 𝐹 : 𝐴𝐵𝐴𝑉 ) → ( ( 𝑦𝑃 ↦ ( ( I ↾ ( 𝐹𝐴 ) ) ‘ ( 𝐹𝑦 ) ) ) ∘ ( 𝑎𝐴 ↦ ( 𝐹 “ { ( 𝐹𝑎 ) } ) ) ) = ( 𝑎𝐴 ↦ ( ( I ↾ ( 𝐹𝐴 ) ) ‘ ( 𝐹 “ ( 𝐹 “ { ( 𝐹𝑎 ) } ) ) ) ) )
54 dffn5 ( 𝐹 Fn 𝐴𝐹 = ( 𝑎𝐴 ↦ ( 𝐹𝑎 ) ) )
55 12 54 sylib ( 𝐹 : 𝐴𝐵𝐹 = ( 𝑎𝐴 ↦ ( 𝐹𝑎 ) ) )
56 55 adantr ( ( 𝐹 : 𝐴𝐵𝐴𝑉 ) → 𝐹 = ( 𝑎𝐴 ↦ ( 𝐹𝑎 ) ) )
57 42 53 56 3eqtr4rd ( ( 𝐹 : 𝐴𝐵𝐴𝑉 ) → 𝐹 = ( ( 𝑦𝑃 ↦ ( ( I ↾ ( 𝐹𝐴 ) ) ‘ ( 𝐹𝑦 ) ) ) ∘ ( 𝑎𝐴 ↦ ( 𝐹 “ { ( 𝐹𝑎 ) } ) ) ) )
58 f1of ( ( I ↾ ( 𝐹𝐴 ) ) : ( 𝐹𝐴 ) –1-1-onto→ ( 𝐹𝐴 ) → ( I ↾ ( 𝐹𝐴 ) ) : ( 𝐹𝐴 ) ⟶ ( 𝐹𝐴 ) )
59 22 58 mp1i ( 𝐹 Fn 𝐴 → ( I ↾ ( 𝐹𝐴 ) ) : ( 𝐹𝐴 ) ⟶ ( 𝐹𝐴 ) )
60 fnima ( 𝐹 Fn 𝐴 → ( 𝐹𝐴 ) = ran 𝐹 )
61 60 eqcomd ( 𝐹 Fn 𝐴 → ran 𝐹 = ( 𝐹𝐴 ) )
62 61 feq2d ( 𝐹 Fn 𝐴 → ( ( I ↾ ( 𝐹𝐴 ) ) : ran 𝐹 ⟶ ( 𝐹𝐴 ) ↔ ( I ↾ ( 𝐹𝐴 ) ) : ( 𝐹𝐴 ) ⟶ ( 𝐹𝐴 ) ) )
63 59 62 mpbird ( 𝐹 Fn 𝐴 → ( I ↾ ( 𝐹𝐴 ) ) : ran 𝐹 ⟶ ( 𝐹𝐴 ) )
64 1 uniimaelsetpreimafv ( ( 𝐹 Fn 𝐴𝑦𝑃 ) → ( 𝐹𝑦 ) ∈ ran 𝐹 )
65 63 64 cofmpt ( 𝐹 Fn 𝐴 → ( ( I ↾ ( 𝐹𝐴 ) ) ∘ ( 𝑦𝑃 ( 𝐹𝑦 ) ) ) = ( 𝑦𝑃 ↦ ( ( I ↾ ( 𝐹𝐴 ) ) ‘ ( 𝐹𝑦 ) ) ) )
66 65 eqcomd ( 𝐹 Fn 𝐴 → ( 𝑦𝑃 ↦ ( ( I ↾ ( 𝐹𝐴 ) ) ‘ ( 𝐹𝑦 ) ) ) = ( ( I ↾ ( 𝐹𝐴 ) ) ∘ ( 𝑦𝑃 ( 𝐹𝑦 ) ) ) )
67 31 66 syl ( ( 𝐹 : 𝐴𝐵𝐴𝑉 ) → ( 𝑦𝑃 ↦ ( ( I ↾ ( 𝐹𝐴 ) ) ‘ ( 𝐹𝑦 ) ) ) = ( ( I ↾ ( 𝐹𝐴 ) ) ∘ ( 𝑦𝑃 ( 𝐹𝑦 ) ) ) )
68 67 coeq1d ( ( 𝐹 : 𝐴𝐵𝐴𝑉 ) → ( ( 𝑦𝑃 ↦ ( ( I ↾ ( 𝐹𝐴 ) ) ‘ ( 𝐹𝑦 ) ) ) ∘ ( 𝑎𝐴 ↦ ( 𝐹 “ { ( 𝐹𝑎 ) } ) ) ) = ( ( ( I ↾ ( 𝐹𝐴 ) ) ∘ ( 𝑦𝑃 ( 𝐹𝑦 ) ) ) ∘ ( 𝑎𝐴 ↦ ( 𝐹 “ { ( 𝐹𝑎 ) } ) ) ) )
69 57 68 eqtrd ( ( 𝐹 : 𝐴𝐵𝐴𝑉 ) → 𝐹 = ( ( ( I ↾ ( 𝐹𝐴 ) ) ∘ ( 𝑦𝑃 ( 𝐹𝑦 ) ) ) ∘ ( 𝑎𝐴 ↦ ( 𝐹 “ { ( 𝐹𝑎 ) } ) ) ) )
70 30 69 jca ( ( 𝐹 : 𝐴𝐵𝐴𝑉 ) → ( ( ( 𝑎𝐴 ↦ ( 𝐹 “ { ( 𝐹𝑎 ) } ) ) : 𝐴onto𝑃 ∧ ( 𝑦𝑃 ( 𝐹𝑦 ) ) : 𝑃1-1-onto→ ( 𝐹𝐴 ) ∧ ( I ↾ ( 𝐹𝐴 ) ) : ( 𝐹𝐴 ) –1-1𝐵 ) ∧ 𝐹 = ( ( ( I ↾ ( 𝐹𝐴 ) ) ∘ ( 𝑦𝑃 ( 𝐹𝑦 ) ) ) ∘ ( 𝑎𝐴 ↦ ( 𝐹 “ { ( 𝐹𝑎 ) } ) ) ) ) )
71 foeq1 ( 𝑔 = ( 𝑎𝐴 ↦ ( 𝐹 “ { ( 𝐹𝑎 ) } ) ) → ( 𝑔 : 𝐴onto𝑃 ↔ ( 𝑎𝐴 ↦ ( 𝐹 “ { ( 𝐹𝑎 ) } ) ) : 𝐴onto𝑃 ) )
72 71 3ad2ant1 ( ( 𝑔 = ( 𝑎𝐴 ↦ ( 𝐹 “ { ( 𝐹𝑎 ) } ) ) ∧ = ( 𝑦𝑃 ( 𝐹𝑦 ) ) ∧ 𝑖 = ( I ↾ ( 𝐹𝐴 ) ) ) → ( 𝑔 : 𝐴onto𝑃 ↔ ( 𝑎𝐴 ↦ ( 𝐹 “ { ( 𝐹𝑎 ) } ) ) : 𝐴onto𝑃 ) )
73 f1oeq1 ( = ( 𝑦𝑃 ( 𝐹𝑦 ) ) → ( : 𝑃1-1-onto→ ( 𝐹𝐴 ) ↔ ( 𝑦𝑃 ( 𝐹𝑦 ) ) : 𝑃1-1-onto→ ( 𝐹𝐴 ) ) )
74 73 3ad2ant2 ( ( 𝑔 = ( 𝑎𝐴 ↦ ( 𝐹 “ { ( 𝐹𝑎 ) } ) ) ∧ = ( 𝑦𝑃 ( 𝐹𝑦 ) ) ∧ 𝑖 = ( I ↾ ( 𝐹𝐴 ) ) ) → ( : 𝑃1-1-onto→ ( 𝐹𝐴 ) ↔ ( 𝑦𝑃 ( 𝐹𝑦 ) ) : 𝑃1-1-onto→ ( 𝐹𝐴 ) ) )
75 f1eq1 ( 𝑖 = ( I ↾ ( 𝐹𝐴 ) ) → ( 𝑖 : ( 𝐹𝐴 ) –1-1𝐵 ↔ ( I ↾ ( 𝐹𝐴 ) ) : ( 𝐹𝐴 ) –1-1𝐵 ) )
76 75 3ad2ant3 ( ( 𝑔 = ( 𝑎𝐴 ↦ ( 𝐹 “ { ( 𝐹𝑎 ) } ) ) ∧ = ( 𝑦𝑃 ( 𝐹𝑦 ) ) ∧ 𝑖 = ( I ↾ ( 𝐹𝐴 ) ) ) → ( 𝑖 : ( 𝐹𝐴 ) –1-1𝐵 ↔ ( I ↾ ( 𝐹𝐴 ) ) : ( 𝐹𝐴 ) –1-1𝐵 ) )
77 72 74 76 3anbi123d ( ( 𝑔 = ( 𝑎𝐴 ↦ ( 𝐹 “ { ( 𝐹𝑎 ) } ) ) ∧ = ( 𝑦𝑃 ( 𝐹𝑦 ) ) ∧ 𝑖 = ( I ↾ ( 𝐹𝐴 ) ) ) → ( ( 𝑔 : 𝐴onto𝑃 : 𝑃1-1-onto→ ( 𝐹𝐴 ) ∧ 𝑖 : ( 𝐹𝐴 ) –1-1𝐵 ) ↔ ( ( 𝑎𝐴 ↦ ( 𝐹 “ { ( 𝐹𝑎 ) } ) ) : 𝐴onto𝑃 ∧ ( 𝑦𝑃 ( 𝐹𝑦 ) ) : 𝑃1-1-onto→ ( 𝐹𝐴 ) ∧ ( I ↾ ( 𝐹𝐴 ) ) : ( 𝐹𝐴 ) –1-1𝐵 ) ) )
78 simp3 ( ( 𝑔 = ( 𝑎𝐴 ↦ ( 𝐹 “ { ( 𝐹𝑎 ) } ) ) ∧ = ( 𝑦𝑃 ( 𝐹𝑦 ) ) ∧ 𝑖 = ( I ↾ ( 𝐹𝐴 ) ) ) → 𝑖 = ( I ↾ ( 𝐹𝐴 ) ) )
79 simp2 ( ( 𝑔 = ( 𝑎𝐴 ↦ ( 𝐹 “ { ( 𝐹𝑎 ) } ) ) ∧ = ( 𝑦𝑃 ( 𝐹𝑦 ) ) ∧ 𝑖 = ( I ↾ ( 𝐹𝐴 ) ) ) → = ( 𝑦𝑃 ( 𝐹𝑦 ) ) )
80 78 79 coeq12d ( ( 𝑔 = ( 𝑎𝐴 ↦ ( 𝐹 “ { ( 𝐹𝑎 ) } ) ) ∧ = ( 𝑦𝑃 ( 𝐹𝑦 ) ) ∧ 𝑖 = ( I ↾ ( 𝐹𝐴 ) ) ) → ( 𝑖 ) = ( ( I ↾ ( 𝐹𝐴 ) ) ∘ ( 𝑦𝑃 ( 𝐹𝑦 ) ) ) )
81 simp1 ( ( 𝑔 = ( 𝑎𝐴 ↦ ( 𝐹 “ { ( 𝐹𝑎 ) } ) ) ∧ = ( 𝑦𝑃 ( 𝐹𝑦 ) ) ∧ 𝑖 = ( I ↾ ( 𝐹𝐴 ) ) ) → 𝑔 = ( 𝑎𝐴 ↦ ( 𝐹 “ { ( 𝐹𝑎 ) } ) ) )
82 80 81 coeq12d ( ( 𝑔 = ( 𝑎𝐴 ↦ ( 𝐹 “ { ( 𝐹𝑎 ) } ) ) ∧ = ( 𝑦𝑃 ( 𝐹𝑦 ) ) ∧ 𝑖 = ( I ↾ ( 𝐹𝐴 ) ) ) → ( ( 𝑖 ) ∘ 𝑔 ) = ( ( ( I ↾ ( 𝐹𝐴 ) ) ∘ ( 𝑦𝑃 ( 𝐹𝑦 ) ) ) ∘ ( 𝑎𝐴 ↦ ( 𝐹 “ { ( 𝐹𝑎 ) } ) ) ) )
83 82 eqeq2d ( ( 𝑔 = ( 𝑎𝐴 ↦ ( 𝐹 “ { ( 𝐹𝑎 ) } ) ) ∧ = ( 𝑦𝑃 ( 𝐹𝑦 ) ) ∧ 𝑖 = ( I ↾ ( 𝐹𝐴 ) ) ) → ( 𝐹 = ( ( 𝑖 ) ∘ 𝑔 ) ↔ 𝐹 = ( ( ( I ↾ ( 𝐹𝐴 ) ) ∘ ( 𝑦𝑃 ( 𝐹𝑦 ) ) ) ∘ ( 𝑎𝐴 ↦ ( 𝐹 “ { ( 𝐹𝑎 ) } ) ) ) ) )
84 77 83 anbi12d ( ( 𝑔 = ( 𝑎𝐴 ↦ ( 𝐹 “ { ( 𝐹𝑎 ) } ) ) ∧ = ( 𝑦𝑃 ( 𝐹𝑦 ) ) ∧ 𝑖 = ( I ↾ ( 𝐹𝐴 ) ) ) → ( ( ( 𝑔 : 𝐴onto𝑃 : 𝑃1-1-onto→ ( 𝐹𝐴 ) ∧ 𝑖 : ( 𝐹𝐴 ) –1-1𝐵 ) ∧ 𝐹 = ( ( 𝑖 ) ∘ 𝑔 ) ) ↔ ( ( ( 𝑎𝐴 ↦ ( 𝐹 “ { ( 𝐹𝑎 ) } ) ) : 𝐴onto𝑃 ∧ ( 𝑦𝑃 ( 𝐹𝑦 ) ) : 𝑃1-1-onto→ ( 𝐹𝐴 ) ∧ ( I ↾ ( 𝐹𝐴 ) ) : ( 𝐹𝐴 ) –1-1𝐵 ) ∧ 𝐹 = ( ( ( I ↾ ( 𝐹𝐴 ) ) ∘ ( 𝑦𝑃 ( 𝐹𝑦 ) ) ) ∘ ( 𝑎𝐴 ↦ ( 𝐹 “ { ( 𝐹𝑎 ) } ) ) ) ) ) )
85 84 spc3egv ( ( ( 𝑎𝐴 ↦ ( 𝐹 “ { ( 𝐹𝑎 ) } ) ) ∈ V ∧ ( 𝑦𝑃 ( 𝐹𝑦 ) ) ∈ V ∧ ( I ↾ ( 𝐹𝐴 ) ) ∈ V ) → ( ( ( ( 𝑎𝐴 ↦ ( 𝐹 “ { ( 𝐹𝑎 ) } ) ) : 𝐴onto𝑃 ∧ ( 𝑦𝑃 ( 𝐹𝑦 ) ) : 𝑃1-1-onto→ ( 𝐹𝐴 ) ∧ ( I ↾ ( 𝐹𝐴 ) ) : ( 𝐹𝐴 ) –1-1𝐵 ) ∧ 𝐹 = ( ( ( I ↾ ( 𝐹𝐴 ) ) ∘ ( 𝑦𝑃 ( 𝐹𝑦 ) ) ) ∘ ( 𝑎𝐴 ↦ ( 𝐹 “ { ( 𝐹𝑎 ) } ) ) ) ) → ∃ 𝑔𝑖 ( ( 𝑔 : 𝐴onto𝑃 : 𝑃1-1-onto→ ( 𝐹𝐴 ) ∧ 𝑖 : ( 𝐹𝐴 ) –1-1𝐵 ) ∧ 𝐹 = ( ( 𝑖 ) ∘ 𝑔 ) ) ) )
86 11 70 85 sylc ( ( 𝐹 : 𝐴𝐵𝐴𝑉 ) → ∃ 𝑔𝑖 ( ( 𝑔 : 𝐴onto𝑃 : 𝑃1-1-onto→ ( 𝐹𝐴 ) ∧ 𝑖 : ( 𝐹𝐴 ) –1-1𝐵 ) ∧ 𝐹 = ( ( 𝑖 ) ∘ 𝑔 ) ) )