Metamath Proof Explorer


Theorem fprodcom2

Description: Interchange order of multiplication. Note that B ( j ) and D ( k ) are not necessarily constant expressions. (Contributed by Scott Fenton, 1-Feb-2018) (Proof shortened by JJ, 2-Aug-2021)

Ref Expression
Hypotheses fprodcom2.1 ( 𝜑𝐴 ∈ Fin )
fprodcom2.2 ( 𝜑𝐶 ∈ Fin )
fprodcom2.3 ( ( 𝜑𝑗𝐴 ) → 𝐵 ∈ Fin )
fprodcom2.4 ( 𝜑 → ( ( 𝑗𝐴𝑘𝐵 ) ↔ ( 𝑘𝐶𝑗𝐷 ) ) )
fprodcom2.5 ( ( 𝜑 ∧ ( 𝑗𝐴𝑘𝐵 ) ) → 𝐸 ∈ ℂ )
Assertion fprodcom2 ( 𝜑 → ∏ 𝑗𝐴𝑘𝐵 𝐸 = ∏ 𝑘𝐶𝑗𝐷 𝐸 )

Proof

Step Hyp Ref Expression
1 fprodcom2.1 ( 𝜑𝐴 ∈ Fin )
2 fprodcom2.2 ( 𝜑𝐶 ∈ Fin )
3 fprodcom2.3 ( ( 𝜑𝑗𝐴 ) → 𝐵 ∈ Fin )
4 fprodcom2.4 ( 𝜑 → ( ( 𝑗𝐴𝑘𝐵 ) ↔ ( 𝑘𝐶𝑗𝐷 ) ) )
5 fprodcom2.5 ( ( 𝜑 ∧ ( 𝑗𝐴𝑘𝐵 ) ) → 𝐸 ∈ ℂ )
6 relxp Rel ( { 𝑗 } × 𝐵 )
7 6 rgenw 𝑗𝐴 Rel ( { 𝑗 } × 𝐵 )
8 reliun ( Rel 𝑗𝐴 ( { 𝑗 } × 𝐵 ) ↔ ∀ 𝑗𝐴 Rel ( { 𝑗 } × 𝐵 ) )
9 7 8 mpbir Rel 𝑗𝐴 ( { 𝑗 } × 𝐵 )
10 relcnv Rel 𝑘𝐶 ( { 𝑘 } × 𝐷 )
11 ancom ( ( 𝑥 = 𝑗𝑦 = 𝑘 ) ↔ ( 𝑦 = 𝑘𝑥 = 𝑗 ) )
12 vex 𝑥 ∈ V
13 vex 𝑦 ∈ V
14 12 13 opth ( ⟨ 𝑥 , 𝑦 ⟩ = ⟨ 𝑗 , 𝑘 ⟩ ↔ ( 𝑥 = 𝑗𝑦 = 𝑘 ) )
15 13 12 opth ( ⟨ 𝑦 , 𝑥 ⟩ = ⟨ 𝑘 , 𝑗 ⟩ ↔ ( 𝑦 = 𝑘𝑥 = 𝑗 ) )
16 11 14 15 3bitr4i ( ⟨ 𝑥 , 𝑦 ⟩ = ⟨ 𝑗 , 𝑘 ⟩ ↔ ⟨ 𝑦 , 𝑥 ⟩ = ⟨ 𝑘 , 𝑗 ⟩ )
17 16 a1i ( 𝜑 → ( ⟨ 𝑥 , 𝑦 ⟩ = ⟨ 𝑗 , 𝑘 ⟩ ↔ ⟨ 𝑦 , 𝑥 ⟩ = ⟨ 𝑘 , 𝑗 ⟩ ) )
18 17 4 anbi12d ( 𝜑 → ( ( ⟨ 𝑥 , 𝑦 ⟩ = ⟨ 𝑗 , 𝑘 ⟩ ∧ ( 𝑗𝐴𝑘𝐵 ) ) ↔ ( ⟨ 𝑦 , 𝑥 ⟩ = ⟨ 𝑘 , 𝑗 ⟩ ∧ ( 𝑘𝐶𝑗𝐷 ) ) ) )
19 18 2exbidv ( 𝜑 → ( ∃ 𝑗𝑘 ( ⟨ 𝑥 , 𝑦 ⟩ = ⟨ 𝑗 , 𝑘 ⟩ ∧ ( 𝑗𝐴𝑘𝐵 ) ) ↔ ∃ 𝑗𝑘 ( ⟨ 𝑦 , 𝑥 ⟩ = ⟨ 𝑘 , 𝑗 ⟩ ∧ ( 𝑘𝐶𝑗𝐷 ) ) ) )
20 eliunxp ( ⟨ 𝑥 , 𝑦 ⟩ ∈ 𝑗𝐴 ( { 𝑗 } × 𝐵 ) ↔ ∃ 𝑗𝑘 ( ⟨ 𝑥 , 𝑦 ⟩ = ⟨ 𝑗 , 𝑘 ⟩ ∧ ( 𝑗𝐴𝑘𝐵 ) ) )
21 12 13 opelcnv ( ⟨ 𝑥 , 𝑦 ⟩ ∈ 𝑘𝐶 ( { 𝑘 } × 𝐷 ) ↔ ⟨ 𝑦 , 𝑥 ⟩ ∈ 𝑘𝐶 ( { 𝑘 } × 𝐷 ) )
22 eliunxp ( ⟨ 𝑦 , 𝑥 ⟩ ∈ 𝑘𝐶 ( { 𝑘 } × 𝐷 ) ↔ ∃ 𝑘𝑗 ( ⟨ 𝑦 , 𝑥 ⟩ = ⟨ 𝑘 , 𝑗 ⟩ ∧ ( 𝑘𝐶𝑗𝐷 ) ) )
23 excom ( ∃ 𝑘𝑗 ( ⟨ 𝑦 , 𝑥 ⟩ = ⟨ 𝑘 , 𝑗 ⟩ ∧ ( 𝑘𝐶𝑗𝐷 ) ) ↔ ∃ 𝑗𝑘 ( ⟨ 𝑦 , 𝑥 ⟩ = ⟨ 𝑘 , 𝑗 ⟩ ∧ ( 𝑘𝐶𝑗𝐷 ) ) )
24 21 22 23 3bitri ( ⟨ 𝑥 , 𝑦 ⟩ ∈ 𝑘𝐶 ( { 𝑘 } × 𝐷 ) ↔ ∃ 𝑗𝑘 ( ⟨ 𝑦 , 𝑥 ⟩ = ⟨ 𝑘 , 𝑗 ⟩ ∧ ( 𝑘𝐶𝑗𝐷 ) ) )
25 19 20 24 3bitr4g ( 𝜑 → ( ⟨ 𝑥 , 𝑦 ⟩ ∈ 𝑗𝐴 ( { 𝑗 } × 𝐵 ) ↔ ⟨ 𝑥 , 𝑦 ⟩ ∈ 𝑘𝐶 ( { 𝑘 } × 𝐷 ) ) )
26 9 10 25 eqrelrdv ( 𝜑 𝑗𝐴 ( { 𝑗 } × 𝐵 ) = 𝑘𝐶 ( { 𝑘 } × 𝐷 ) )
27 nfcv 𝑥 ( { 𝑗 } × 𝐵 )
28 nfcv 𝑗 { 𝑥 }
29 nfcsb1v 𝑗 𝑥 / 𝑗 𝐵
30 28 29 nfxp 𝑗 ( { 𝑥 } × 𝑥 / 𝑗 𝐵 )
31 sneq ( 𝑗 = 𝑥 → { 𝑗 } = { 𝑥 } )
32 csbeq1a ( 𝑗 = 𝑥𝐵 = 𝑥 / 𝑗 𝐵 )
33 31 32 xpeq12d ( 𝑗 = 𝑥 → ( { 𝑗 } × 𝐵 ) = ( { 𝑥 } × 𝑥 / 𝑗 𝐵 ) )
34 27 30 33 cbviun 𝑗𝐴 ( { 𝑗 } × 𝐵 ) = 𝑥𝐴 ( { 𝑥 } × 𝑥 / 𝑗 𝐵 )
35 nfcv 𝑦 ( { 𝑘 } × 𝐷 )
36 nfcv 𝑘 { 𝑦 }
37 nfcsb1v 𝑘 𝑦 / 𝑘 𝐷
38 36 37 nfxp 𝑘 ( { 𝑦 } × 𝑦 / 𝑘 𝐷 )
39 sneq ( 𝑘 = 𝑦 → { 𝑘 } = { 𝑦 } )
40 csbeq1a ( 𝑘 = 𝑦𝐷 = 𝑦 / 𝑘 𝐷 )
41 39 40 xpeq12d ( 𝑘 = 𝑦 → ( { 𝑘 } × 𝐷 ) = ( { 𝑦 } × 𝑦 / 𝑘 𝐷 ) )
42 35 38 41 cbviun 𝑘𝐶 ( { 𝑘 } × 𝐷 ) = 𝑦𝐶 ( { 𝑦 } × 𝑦 / 𝑘 𝐷 )
43 42 cnveqi 𝑘𝐶 ( { 𝑘 } × 𝐷 ) = 𝑦𝐶 ( { 𝑦 } × 𝑦 / 𝑘 𝐷 )
44 26 34 43 3eqtr3g ( 𝜑 𝑥𝐴 ( { 𝑥 } × 𝑥 / 𝑗 𝐵 ) = 𝑦𝐶 ( { 𝑦 } × 𝑦 / 𝑘 𝐷 ) )
45 44 prodeq1d ( 𝜑 → ∏ 𝑧 𝑥𝐴 ( { 𝑥 } × 𝑥 / 𝑗 𝐵 ) ( 2nd𝑧 ) / 𝑘 ( 1st𝑧 ) / 𝑗 𝐸 = ∏ 𝑧 𝑦𝐶 ( { 𝑦 } × 𝑦 / 𝑘 𝐷 ) ( 2nd𝑧 ) / 𝑘 ( 1st𝑧 ) / 𝑗 𝐸 )
46 13 12 op1std ( 𝑤 = ⟨ 𝑦 , 𝑥 ⟩ → ( 1st𝑤 ) = 𝑦 )
47 46 csbeq1d ( 𝑤 = ⟨ 𝑦 , 𝑥 ⟩ → ( 1st𝑤 ) / 𝑘 ( 2nd𝑤 ) / 𝑗 𝐸 = 𝑦 / 𝑘 ( 2nd𝑤 ) / 𝑗 𝐸 )
48 13 12 op2ndd ( 𝑤 = ⟨ 𝑦 , 𝑥 ⟩ → ( 2nd𝑤 ) = 𝑥 )
49 48 csbeq1d ( 𝑤 = ⟨ 𝑦 , 𝑥 ⟩ → ( 2nd𝑤 ) / 𝑗 𝐸 = 𝑥 / 𝑗 𝐸 )
50 49 csbeq2dv ( 𝑤 = ⟨ 𝑦 , 𝑥 ⟩ → 𝑦 / 𝑘 ( 2nd𝑤 ) / 𝑗 𝐸 = 𝑦 / 𝑘 𝑥 / 𝑗 𝐸 )
51 47 50 eqtrd ( 𝑤 = ⟨ 𝑦 , 𝑥 ⟩ → ( 1st𝑤 ) / 𝑘 ( 2nd𝑤 ) / 𝑗 𝐸 = 𝑦 / 𝑘 𝑥 / 𝑗 𝐸 )
52 12 13 op2ndd ( 𝑧 = ⟨ 𝑥 , 𝑦 ⟩ → ( 2nd𝑧 ) = 𝑦 )
53 52 csbeq1d ( 𝑧 = ⟨ 𝑥 , 𝑦 ⟩ → ( 2nd𝑧 ) / 𝑘 ( 1st𝑧 ) / 𝑗 𝐸 = 𝑦 / 𝑘 ( 1st𝑧 ) / 𝑗 𝐸 )
54 12 13 op1std ( 𝑧 = ⟨ 𝑥 , 𝑦 ⟩ → ( 1st𝑧 ) = 𝑥 )
55 54 csbeq1d ( 𝑧 = ⟨ 𝑥 , 𝑦 ⟩ → ( 1st𝑧 ) / 𝑗 𝐸 = 𝑥 / 𝑗 𝐸 )
56 55 csbeq2dv ( 𝑧 = ⟨ 𝑥 , 𝑦 ⟩ → 𝑦 / 𝑘 ( 1st𝑧 ) / 𝑗 𝐸 = 𝑦 / 𝑘 𝑥 / 𝑗 𝐸 )
57 53 56 eqtrd ( 𝑧 = ⟨ 𝑥 , 𝑦 ⟩ → ( 2nd𝑧 ) / 𝑘 ( 1st𝑧 ) / 𝑗 𝐸 = 𝑦 / 𝑘 𝑥 / 𝑗 𝐸 )
58 snfi { 𝑦 } ∈ Fin
59 1 adantr ( ( 𝜑𝑦𝐶 ) → 𝐴 ∈ Fin )
60 37 40 opeliunxp2f ( ⟨ 𝑦 , 𝑥 ⟩ ∈ 𝑘𝐶 ( { 𝑘 } × 𝐷 ) ↔ ( 𝑦𝐶𝑥 𝑦 / 𝑘 𝐷 ) )
61 21 60 sylbbr ( ( 𝑦𝐶𝑥 𝑦 / 𝑘 𝐷 ) → ⟨ 𝑥 , 𝑦 ⟩ ∈ 𝑘𝐶 ( { 𝑘 } × 𝐷 ) )
62 61 adantl ( ( 𝜑 ∧ ( 𝑦𝐶𝑥 𝑦 / 𝑘 𝐷 ) ) → ⟨ 𝑥 , 𝑦 ⟩ ∈ 𝑘𝐶 ( { 𝑘 } × 𝐷 ) )
63 26 adantr ( ( 𝜑 ∧ ( 𝑦𝐶𝑥 𝑦 / 𝑘 𝐷 ) ) → 𝑗𝐴 ( { 𝑗 } × 𝐵 ) = 𝑘𝐶 ( { 𝑘 } × 𝐷 ) )
64 62 63 eleqtrrd ( ( 𝜑 ∧ ( 𝑦𝐶𝑥 𝑦 / 𝑘 𝐷 ) ) → ⟨ 𝑥 , 𝑦 ⟩ ∈ 𝑗𝐴 ( { 𝑗 } × 𝐵 ) )
65 eliun ( ⟨ 𝑥 , 𝑦 ⟩ ∈ 𝑗𝐴 ( { 𝑗 } × 𝐵 ) ↔ ∃ 𝑗𝐴𝑥 , 𝑦 ⟩ ∈ ( { 𝑗 } × 𝐵 ) )
66 64 65 sylib ( ( 𝜑 ∧ ( 𝑦𝐶𝑥 𝑦 / 𝑘 𝐷 ) ) → ∃ 𝑗𝐴𝑥 , 𝑦 ⟩ ∈ ( { 𝑗 } × 𝐵 ) )
67 simpr ( ( 𝑗𝐴 ∧ ⟨ 𝑥 , 𝑦 ⟩ ∈ ( { 𝑗 } × 𝐵 ) ) → ⟨ 𝑥 , 𝑦 ⟩ ∈ ( { 𝑗 } × 𝐵 ) )
68 opelxp ( ⟨ 𝑥 , 𝑦 ⟩ ∈ ( { 𝑗 } × 𝐵 ) ↔ ( 𝑥 ∈ { 𝑗 } ∧ 𝑦𝐵 ) )
69 67 68 sylib ( ( 𝑗𝐴 ∧ ⟨ 𝑥 , 𝑦 ⟩ ∈ ( { 𝑗 } × 𝐵 ) ) → ( 𝑥 ∈ { 𝑗 } ∧ 𝑦𝐵 ) )
70 69 simpld ( ( 𝑗𝐴 ∧ ⟨ 𝑥 , 𝑦 ⟩ ∈ ( { 𝑗 } × 𝐵 ) ) → 𝑥 ∈ { 𝑗 } )
71 elsni ( 𝑥 ∈ { 𝑗 } → 𝑥 = 𝑗 )
72 70 71 syl ( ( 𝑗𝐴 ∧ ⟨ 𝑥 , 𝑦 ⟩ ∈ ( { 𝑗 } × 𝐵 ) ) → 𝑥 = 𝑗 )
73 simpl ( ( 𝑗𝐴 ∧ ⟨ 𝑥 , 𝑦 ⟩ ∈ ( { 𝑗 } × 𝐵 ) ) → 𝑗𝐴 )
74 72 73 eqeltrd ( ( 𝑗𝐴 ∧ ⟨ 𝑥 , 𝑦 ⟩ ∈ ( { 𝑗 } × 𝐵 ) ) → 𝑥𝐴 )
75 74 rexlimiva ( ∃ 𝑗𝐴𝑥 , 𝑦 ⟩ ∈ ( { 𝑗 } × 𝐵 ) → 𝑥𝐴 )
76 66 75 syl ( ( 𝜑 ∧ ( 𝑦𝐶𝑥 𝑦 / 𝑘 𝐷 ) ) → 𝑥𝐴 )
77 76 expr ( ( 𝜑𝑦𝐶 ) → ( 𝑥 𝑦 / 𝑘 𝐷𝑥𝐴 ) )
78 77 ssrdv ( ( 𝜑𝑦𝐶 ) → 𝑦 / 𝑘 𝐷𝐴 )
79 59 78 ssfid ( ( 𝜑𝑦𝐶 ) → 𝑦 / 𝑘 𝐷 ∈ Fin )
80 xpfi ( ( { 𝑦 } ∈ Fin ∧ 𝑦 / 𝑘 𝐷 ∈ Fin ) → ( { 𝑦 } × 𝑦 / 𝑘 𝐷 ) ∈ Fin )
81 58 79 80 sylancr ( ( 𝜑𝑦𝐶 ) → ( { 𝑦 } × 𝑦 / 𝑘 𝐷 ) ∈ Fin )
82 81 ralrimiva ( 𝜑 → ∀ 𝑦𝐶 ( { 𝑦 } × 𝑦 / 𝑘 𝐷 ) ∈ Fin )
83 iunfi ( ( 𝐶 ∈ Fin ∧ ∀ 𝑦𝐶 ( { 𝑦 } × 𝑦 / 𝑘 𝐷 ) ∈ Fin ) → 𝑦𝐶 ( { 𝑦 } × 𝑦 / 𝑘 𝐷 ) ∈ Fin )
84 2 82 83 syl2anc ( 𝜑 𝑦𝐶 ( { 𝑦 } × 𝑦 / 𝑘 𝐷 ) ∈ Fin )
85 reliun ( Rel 𝑦𝐶 ( { 𝑦 } × 𝑦 / 𝑘 𝐷 ) ↔ ∀ 𝑦𝐶 Rel ( { 𝑦 } × 𝑦 / 𝑘 𝐷 ) )
86 relxp Rel ( { 𝑦 } × 𝑦 / 𝑘 𝐷 )
87 86 a1i ( 𝑦𝐶 → Rel ( { 𝑦 } × 𝑦 / 𝑘 𝐷 ) )
88 85 87 mprgbir Rel 𝑦𝐶 ( { 𝑦 } × 𝑦 / 𝑘 𝐷 )
89 88 a1i ( 𝜑 → Rel 𝑦𝐶 ( { 𝑦 } × 𝑦 / 𝑘 𝐷 ) )
90 csbeq1 ( 𝑥 = ( 2nd𝑤 ) → 𝑥 / 𝑗 𝐸 = ( 2nd𝑤 ) / 𝑗 𝐸 )
91 90 csbeq2dv ( 𝑥 = ( 2nd𝑤 ) → ( 1st𝑤 ) / 𝑘 𝑥 / 𝑗 𝐸 = ( 1st𝑤 ) / 𝑘 ( 2nd𝑤 ) / 𝑗 𝐸 )
92 91 eleq1d ( 𝑥 = ( 2nd𝑤 ) → ( ( 1st𝑤 ) / 𝑘 𝑥 / 𝑗 𝐸 ∈ ℂ ↔ ( 1st𝑤 ) / 𝑘 ( 2nd𝑤 ) / 𝑗 𝐸 ∈ ℂ ) )
93 csbeq1 ( 𝑦 = ( 1st𝑤 ) → 𝑦 / 𝑘 𝐷 = ( 1st𝑤 ) / 𝑘 𝐷 )
94 csbeq1 ( 𝑦 = ( 1st𝑤 ) → 𝑦 / 𝑘 𝑥 / 𝑗 𝐸 = ( 1st𝑤 ) / 𝑘 𝑥 / 𝑗 𝐸 )
95 94 eleq1d ( 𝑦 = ( 1st𝑤 ) → ( 𝑦 / 𝑘 𝑥 / 𝑗 𝐸 ∈ ℂ ↔ ( 1st𝑤 ) / 𝑘 𝑥 / 𝑗 𝐸 ∈ ℂ ) )
96 93 95 raleqbidv ( 𝑦 = ( 1st𝑤 ) → ( ∀ 𝑥 𝑦 / 𝑘 𝐷 𝑦 / 𝑘 𝑥 / 𝑗 𝐸 ∈ ℂ ↔ ∀ 𝑥 ( 1st𝑤 ) / 𝑘 𝐷 ( 1st𝑤 ) / 𝑘 𝑥 / 𝑗 𝐸 ∈ ℂ ) )
97 simpl ( ( 𝜑 ∧ ( 𝑦𝐶𝑥 𝑦 / 𝑘 𝐷 ) ) → 𝜑 )
98 29 nfcri 𝑗 𝑦 𝑥 / 𝑗 𝐵
99 71 equcomd ( 𝑥 ∈ { 𝑗 } → 𝑗 = 𝑥 )
100 99 32 syl ( 𝑥 ∈ { 𝑗 } → 𝐵 = 𝑥 / 𝑗 𝐵 )
101 100 eleq2d ( 𝑥 ∈ { 𝑗 } → ( 𝑦𝐵𝑦 𝑥 / 𝑗 𝐵 ) )
102 101 biimpa ( ( 𝑥 ∈ { 𝑗 } ∧ 𝑦𝐵 ) → 𝑦 𝑥 / 𝑗 𝐵 )
103 68 102 sylbi ( ⟨ 𝑥 , 𝑦 ⟩ ∈ ( { 𝑗 } × 𝐵 ) → 𝑦 𝑥 / 𝑗 𝐵 )
104 103 a1i ( 𝑗𝐴 → ( ⟨ 𝑥 , 𝑦 ⟩ ∈ ( { 𝑗 } × 𝐵 ) → 𝑦 𝑥 / 𝑗 𝐵 ) )
105 98 104 rexlimi ( ∃ 𝑗𝐴𝑥 , 𝑦 ⟩ ∈ ( { 𝑗 } × 𝐵 ) → 𝑦 𝑥 / 𝑗 𝐵 )
106 66 105 syl ( ( 𝜑 ∧ ( 𝑦𝐶𝑥 𝑦 / 𝑘 𝐷 ) ) → 𝑦 𝑥 / 𝑗 𝐵 )
107 5 ralrimivva ( 𝜑 → ∀ 𝑗𝐴𝑘𝐵 𝐸 ∈ ℂ )
108 nfcsb1v 𝑗 𝑥 / 𝑗 𝐸
109 108 nfel1 𝑗 𝑥 / 𝑗 𝐸 ∈ ℂ
110 29 109 nfralw 𝑗𝑘 𝑥 / 𝑗 𝐵 𝑥 / 𝑗 𝐸 ∈ ℂ
111 csbeq1a ( 𝑗 = 𝑥𝐸 = 𝑥 / 𝑗 𝐸 )
112 111 eleq1d ( 𝑗 = 𝑥 → ( 𝐸 ∈ ℂ ↔ 𝑥 / 𝑗 𝐸 ∈ ℂ ) )
113 32 112 raleqbidv ( 𝑗 = 𝑥 → ( ∀ 𝑘𝐵 𝐸 ∈ ℂ ↔ ∀ 𝑘 𝑥 / 𝑗 𝐵 𝑥 / 𝑗 𝐸 ∈ ℂ ) )
114 110 113 rspc ( 𝑥𝐴 → ( ∀ 𝑗𝐴𝑘𝐵 𝐸 ∈ ℂ → ∀ 𝑘 𝑥 / 𝑗 𝐵 𝑥 / 𝑗 𝐸 ∈ ℂ ) )
115 107 114 mpan9 ( ( 𝜑𝑥𝐴 ) → ∀ 𝑘 𝑥 / 𝑗 𝐵 𝑥 / 𝑗 𝐸 ∈ ℂ )
116 nfcsb1v 𝑘 𝑦 / 𝑘 𝑥 / 𝑗 𝐸
117 116 nfel1 𝑘 𝑦 / 𝑘 𝑥 / 𝑗 𝐸 ∈ ℂ
118 csbeq1a ( 𝑘 = 𝑦 𝑥 / 𝑗 𝐸 = 𝑦 / 𝑘 𝑥 / 𝑗 𝐸 )
119 118 eleq1d ( 𝑘 = 𝑦 → ( 𝑥 / 𝑗 𝐸 ∈ ℂ ↔ 𝑦 / 𝑘 𝑥 / 𝑗 𝐸 ∈ ℂ ) )
120 117 119 rspc ( 𝑦 𝑥 / 𝑗 𝐵 → ( ∀ 𝑘 𝑥 / 𝑗 𝐵 𝑥 / 𝑗 𝐸 ∈ ℂ → 𝑦 / 𝑘 𝑥 / 𝑗 𝐸 ∈ ℂ ) )
121 115 120 syl5com ( ( 𝜑𝑥𝐴 ) → ( 𝑦 𝑥 / 𝑗 𝐵 𝑦 / 𝑘 𝑥 / 𝑗 𝐸 ∈ ℂ ) )
122 121 impr ( ( 𝜑 ∧ ( 𝑥𝐴𝑦 𝑥 / 𝑗 𝐵 ) ) → 𝑦 / 𝑘 𝑥 / 𝑗 𝐸 ∈ ℂ )
123 97 76 106 122 syl12anc ( ( 𝜑 ∧ ( 𝑦𝐶𝑥 𝑦 / 𝑘 𝐷 ) ) → 𝑦 / 𝑘 𝑥 / 𝑗 𝐸 ∈ ℂ )
124 123 ralrimivva ( 𝜑 → ∀ 𝑦𝐶𝑥 𝑦 / 𝑘 𝐷 𝑦 / 𝑘 𝑥 / 𝑗 𝐸 ∈ ℂ )
125 124 adantr ( ( 𝜑𝑤 𝑦𝐶 ( { 𝑦 } × 𝑦 / 𝑘 𝐷 ) ) → ∀ 𝑦𝐶𝑥 𝑦 / 𝑘 𝐷 𝑦 / 𝑘 𝑥 / 𝑗 𝐸 ∈ ℂ )
126 simpr ( ( 𝜑𝑤 𝑦𝐶 ( { 𝑦 } × 𝑦 / 𝑘 𝐷 ) ) → 𝑤 𝑦𝐶 ( { 𝑦 } × 𝑦 / 𝑘 𝐷 ) )
127 eliun ( 𝑤 𝑦𝐶 ( { 𝑦 } × 𝑦 / 𝑘 𝐷 ) ↔ ∃ 𝑦𝐶 𝑤 ∈ ( { 𝑦 } × 𝑦 / 𝑘 𝐷 ) )
128 126 127 sylib ( ( 𝜑𝑤 𝑦𝐶 ( { 𝑦 } × 𝑦 / 𝑘 𝐷 ) ) → ∃ 𝑦𝐶 𝑤 ∈ ( { 𝑦 } × 𝑦 / 𝑘 𝐷 ) )
129 xp1st ( 𝑤 ∈ ( { 𝑦 } × 𝑦 / 𝑘 𝐷 ) → ( 1st𝑤 ) ∈ { 𝑦 } )
130 129 adantl ( ( 𝑦𝐶𝑤 ∈ ( { 𝑦 } × 𝑦 / 𝑘 𝐷 ) ) → ( 1st𝑤 ) ∈ { 𝑦 } )
131 elsni ( ( 1st𝑤 ) ∈ { 𝑦 } → ( 1st𝑤 ) = 𝑦 )
132 130 131 syl ( ( 𝑦𝐶𝑤 ∈ ( { 𝑦 } × 𝑦 / 𝑘 𝐷 ) ) → ( 1st𝑤 ) = 𝑦 )
133 simpl ( ( 𝑦𝐶𝑤 ∈ ( { 𝑦 } × 𝑦 / 𝑘 𝐷 ) ) → 𝑦𝐶 )
134 132 133 eqeltrd ( ( 𝑦𝐶𝑤 ∈ ( { 𝑦 } × 𝑦 / 𝑘 𝐷 ) ) → ( 1st𝑤 ) ∈ 𝐶 )
135 134 rexlimiva ( ∃ 𝑦𝐶 𝑤 ∈ ( { 𝑦 } × 𝑦 / 𝑘 𝐷 ) → ( 1st𝑤 ) ∈ 𝐶 )
136 128 135 syl ( ( 𝜑𝑤 𝑦𝐶 ( { 𝑦 } × 𝑦 / 𝑘 𝐷 ) ) → ( 1st𝑤 ) ∈ 𝐶 )
137 96 125 136 rspcdva ( ( 𝜑𝑤 𝑦𝐶 ( { 𝑦 } × 𝑦 / 𝑘 𝐷 ) ) → ∀ 𝑥 ( 1st𝑤 ) / 𝑘 𝐷 ( 1st𝑤 ) / 𝑘 𝑥 / 𝑗 𝐸 ∈ ℂ )
138 xp2nd ( 𝑤 ∈ ( { 𝑦 } × 𝑦 / 𝑘 𝐷 ) → ( 2nd𝑤 ) ∈ 𝑦 / 𝑘 𝐷 )
139 138 adantl ( ( 𝑦𝐶𝑤 ∈ ( { 𝑦 } × 𝑦 / 𝑘 𝐷 ) ) → ( 2nd𝑤 ) ∈ 𝑦 / 𝑘 𝐷 )
140 132 csbeq1d ( ( 𝑦𝐶𝑤 ∈ ( { 𝑦 } × 𝑦 / 𝑘 𝐷 ) ) → ( 1st𝑤 ) / 𝑘 𝐷 = 𝑦 / 𝑘 𝐷 )
141 139 140 eleqtrrd ( ( 𝑦𝐶𝑤 ∈ ( { 𝑦 } × 𝑦 / 𝑘 𝐷 ) ) → ( 2nd𝑤 ) ∈ ( 1st𝑤 ) / 𝑘 𝐷 )
142 141 rexlimiva ( ∃ 𝑦𝐶 𝑤 ∈ ( { 𝑦 } × 𝑦 / 𝑘 𝐷 ) → ( 2nd𝑤 ) ∈ ( 1st𝑤 ) / 𝑘 𝐷 )
143 128 142 syl ( ( 𝜑𝑤 𝑦𝐶 ( { 𝑦 } × 𝑦 / 𝑘 𝐷 ) ) → ( 2nd𝑤 ) ∈ ( 1st𝑤 ) / 𝑘 𝐷 )
144 92 137 143 rspcdva ( ( 𝜑𝑤 𝑦𝐶 ( { 𝑦 } × 𝑦 / 𝑘 𝐷 ) ) → ( 1st𝑤 ) / 𝑘 ( 2nd𝑤 ) / 𝑗 𝐸 ∈ ℂ )
145 51 57 84 89 144 fprodcnv ( 𝜑 → ∏ 𝑤 𝑦𝐶 ( { 𝑦 } × 𝑦 / 𝑘 𝐷 ) ( 1st𝑤 ) / 𝑘 ( 2nd𝑤 ) / 𝑗 𝐸 = ∏ 𝑧 𝑦𝐶 ( { 𝑦 } × 𝑦 / 𝑘 𝐷 ) ( 2nd𝑧 ) / 𝑘 ( 1st𝑧 ) / 𝑗 𝐸 )
146 45 145 eqtr4d ( 𝜑 → ∏ 𝑧 𝑥𝐴 ( { 𝑥 } × 𝑥 / 𝑗 𝐵 ) ( 2nd𝑧 ) / 𝑘 ( 1st𝑧 ) / 𝑗 𝐸 = ∏ 𝑤 𝑦𝐶 ( { 𝑦 } × 𝑦 / 𝑘 𝐷 ) ( 1st𝑤 ) / 𝑘 ( 2nd𝑤 ) / 𝑗 𝐸 )
147 3 ralrimiva ( 𝜑 → ∀ 𝑗𝐴 𝐵 ∈ Fin )
148 29 nfel1 𝑗 𝑥 / 𝑗 𝐵 ∈ Fin
149 32 eleq1d ( 𝑗 = 𝑥 → ( 𝐵 ∈ Fin ↔ 𝑥 / 𝑗 𝐵 ∈ Fin ) )
150 148 149 rspc ( 𝑥𝐴 → ( ∀ 𝑗𝐴 𝐵 ∈ Fin → 𝑥 / 𝑗 𝐵 ∈ Fin ) )
151 147 150 mpan9 ( ( 𝜑𝑥𝐴 ) → 𝑥 / 𝑗 𝐵 ∈ Fin )
152 57 1 151 122 fprod2d ( 𝜑 → ∏ 𝑥𝐴𝑦 𝑥 / 𝑗 𝐵 𝑦 / 𝑘 𝑥 / 𝑗 𝐸 = ∏ 𝑧 𝑥𝐴 ( { 𝑥 } × 𝑥 / 𝑗 𝐵 ) ( 2nd𝑧 ) / 𝑘 ( 1st𝑧 ) / 𝑗 𝐸 )
153 51 2 79 123 fprod2d ( 𝜑 → ∏ 𝑦𝐶𝑥 𝑦 / 𝑘 𝐷 𝑦 / 𝑘 𝑥 / 𝑗 𝐸 = ∏ 𝑤 𝑦𝐶 ( { 𝑦 } × 𝑦 / 𝑘 𝐷 ) ( 1st𝑤 ) / 𝑘 ( 2nd𝑤 ) / 𝑗 𝐸 )
154 146 152 153 3eqtr4d ( 𝜑 → ∏ 𝑥𝐴𝑦 𝑥 / 𝑗 𝐵 𝑦 / 𝑘 𝑥 / 𝑗 𝐸 = ∏ 𝑦𝐶𝑥 𝑦 / 𝑘 𝐷 𝑦 / 𝑘 𝑥 / 𝑗 𝐸 )
155 nfcv 𝑥𝑘𝐵 𝐸
156 nfcv 𝑗 𝑦
157 156 108 nfcsbw 𝑗 𝑦 / 𝑘 𝑥 / 𝑗 𝐸
158 29 157 nfcprod 𝑗𝑦 𝑥 / 𝑗 𝐵 𝑦 / 𝑘 𝑥 / 𝑗 𝐸
159 nfcv 𝑦 𝐸
160 nfcsb1v 𝑘 𝑦 / 𝑘 𝐸
161 csbeq1a ( 𝑘 = 𝑦𝐸 = 𝑦 / 𝑘 𝐸 )
162 159 160 161 cbvprodi 𝑘𝐵 𝐸 = ∏ 𝑦𝐵 𝑦 / 𝑘 𝐸
163 111 csbeq2dv ( 𝑗 = 𝑥 𝑦 / 𝑘 𝐸 = 𝑦 / 𝑘 𝑥 / 𝑗 𝐸 )
164 163 adantr ( ( 𝑗 = 𝑥𝑦𝐵 ) → 𝑦 / 𝑘 𝐸 = 𝑦 / 𝑘 𝑥 / 𝑗 𝐸 )
165 32 164 prodeq12dv ( 𝑗 = 𝑥 → ∏ 𝑦𝐵 𝑦 / 𝑘 𝐸 = ∏ 𝑦 𝑥 / 𝑗 𝐵 𝑦 / 𝑘 𝑥 / 𝑗 𝐸 )
166 162 165 syl5eq ( 𝑗 = 𝑥 → ∏ 𝑘𝐵 𝐸 = ∏ 𝑦 𝑥 / 𝑗 𝐵 𝑦 / 𝑘 𝑥 / 𝑗 𝐸 )
167 155 158 166 cbvprodi 𝑗𝐴𝑘𝐵 𝐸 = ∏ 𝑥𝐴𝑦 𝑥 / 𝑗 𝐵 𝑦 / 𝑘 𝑥 / 𝑗 𝐸
168 nfcv 𝑦𝑗𝐷 𝐸
169 37 116 nfcprod 𝑘𝑥 𝑦 / 𝑘 𝐷 𝑦 / 𝑘 𝑥 / 𝑗 𝐸
170 nfcv 𝑥 𝐸
171 170 108 111 cbvprodi 𝑗𝐷 𝐸 = ∏ 𝑥𝐷 𝑥 / 𝑗 𝐸
172 118 adantr ( ( 𝑘 = 𝑦𝑥𝐷 ) → 𝑥 / 𝑗 𝐸 = 𝑦 / 𝑘 𝑥 / 𝑗 𝐸 )
173 40 172 prodeq12dv ( 𝑘 = 𝑦 → ∏ 𝑥𝐷 𝑥 / 𝑗 𝐸 = ∏ 𝑥 𝑦 / 𝑘 𝐷 𝑦 / 𝑘 𝑥 / 𝑗 𝐸 )
174 171 173 syl5eq ( 𝑘 = 𝑦 → ∏ 𝑗𝐷 𝐸 = ∏ 𝑥 𝑦 / 𝑘 𝐷 𝑦 / 𝑘 𝑥 / 𝑗 𝐸 )
175 168 169 174 cbvprodi 𝑘𝐶𝑗𝐷 𝐸 = ∏ 𝑦𝐶𝑥 𝑦 / 𝑘 𝐷 𝑦 / 𝑘 𝑥 / 𝑗 𝐸
176 154 167 175 3eqtr4g ( 𝜑 → ∏ 𝑗𝐴𝑘𝐵 𝐸 = ∏ 𝑘𝐶𝑗𝐷 𝐸 )