Proof of Theorem fprodsplitdc
| Step | Hyp | Ref
 | Expression | 
| 1 |   | iftrue 3566 | 
. . . . 5
⊢ (𝑘 ∈ 𝐴 → if(𝑘 ∈ 𝐴, 𝐶, 1) = 𝐶) | 
| 2 | 1 | prodeq2i 11727 | 
. . . 4
⊢
∏𝑘 ∈
𝐴 if(𝑘 ∈ 𝐴, 𝐶, 1) = ∏𝑘 ∈ 𝐴 𝐶 | 
| 3 |   | ssun1 3326 | 
. . . . . 6
⊢ 𝐴 ⊆ (𝐴 ∪ 𝐵) | 
| 4 |   | fprodsplitdc.2 | 
. . . . . 6
⊢ (𝜑 → 𝑈 = (𝐴 ∪ 𝐵)) | 
| 5 | 3, 4 | sseqtrrid 3234 | 
. . . . 5
⊢ (𝜑 → 𝐴 ⊆ 𝑈) | 
| 6 | 1 | adantl 277 | 
. . . . . 6
⊢ ((𝜑 ∧ 𝑘 ∈ 𝐴) → if(𝑘 ∈ 𝐴, 𝐶, 1) = 𝐶) | 
| 7 | 5 | sselda 3183 | 
. . . . . . 7
⊢ ((𝜑 ∧ 𝑘 ∈ 𝐴) → 𝑘 ∈ 𝑈) | 
| 8 |   | fprodsplitdc.4 | 
. . . . . . 7
⊢ ((𝜑 ∧ 𝑘 ∈ 𝑈) → 𝐶 ∈ ℂ) | 
| 9 | 7, 8 | syldan 282 | 
. . . . . 6
⊢ ((𝜑 ∧ 𝑘 ∈ 𝐴) → 𝐶 ∈ ℂ) | 
| 10 | 6, 9 | eqeltrd 2273 | 
. . . . 5
⊢ ((𝜑 ∧ 𝑘 ∈ 𝐴) → if(𝑘 ∈ 𝐴, 𝐶, 1) ∈ ℂ) | 
| 11 |   | fprodsplitdc.a | 
. . . . 5
⊢ (𝜑 → ∀𝑗 ∈ 𝑈 DECID 𝑗 ∈ 𝐴) | 
| 12 |   | eldifn 3286 | 
. . . . . . 7
⊢ (𝑘 ∈ (𝑈 ∖ 𝐴) → ¬ 𝑘 ∈ 𝐴) | 
| 13 | 12 | iffalsed 3571 | 
. . . . . 6
⊢ (𝑘 ∈ (𝑈 ∖ 𝐴) → if(𝑘 ∈ 𝐴, 𝐶, 1) = 1) | 
| 14 | 13 | adantl 277 | 
. . . . 5
⊢ ((𝜑 ∧ 𝑘 ∈ (𝑈 ∖ 𝐴)) → if(𝑘 ∈ 𝐴, 𝐶, 1) = 1) | 
| 15 |   | fprodsplitdc.3 | 
. . . . 5
⊢ (𝜑 → 𝑈 ∈ Fin) | 
| 16 | 5, 10, 11, 14, 15 | fprodssdc 11755 | 
. . . 4
⊢ (𝜑 → ∏𝑘 ∈ 𝐴 if(𝑘 ∈ 𝐴, 𝐶, 1) = ∏𝑘 ∈ 𝑈 if(𝑘 ∈ 𝐴, 𝐶, 1)) | 
| 17 | 2, 16 | eqtr3id 2243 | 
. . 3
⊢ (𝜑 → ∏𝑘 ∈ 𝐴 𝐶 = ∏𝑘 ∈ 𝑈 if(𝑘 ∈ 𝐴, 𝐶, 1)) | 
| 18 |   | iftrue 3566 | 
. . . . 5
⊢ (𝑘 ∈ 𝐵 → if(𝑘 ∈ 𝐵, 𝐶, 1) = 𝐶) | 
| 19 | 18 | prodeq2i 11727 | 
. . . 4
⊢
∏𝑘 ∈
𝐵 if(𝑘 ∈ 𝐵, 𝐶, 1) = ∏𝑘 ∈ 𝐵 𝐶 | 
| 20 |   | ssun2 3327 | 
. . . . . 6
⊢ 𝐵 ⊆ (𝐴 ∪ 𝐵) | 
| 21 | 20, 4 | sseqtrrid 3234 | 
. . . . 5
⊢ (𝜑 → 𝐵 ⊆ 𝑈) | 
| 22 | 18 | adantl 277 | 
. . . . . 6
⊢ ((𝜑 ∧ 𝑘 ∈ 𝐵) → if(𝑘 ∈ 𝐵, 𝐶, 1) = 𝐶) | 
| 23 | 21 | sselda 3183 | 
. . . . . . 7
⊢ ((𝜑 ∧ 𝑘 ∈ 𝐵) → 𝑘 ∈ 𝑈) | 
| 24 | 23, 8 | syldan 282 | 
. . . . . 6
⊢ ((𝜑 ∧ 𝑘 ∈ 𝐵) → 𝐶 ∈ ℂ) | 
| 25 | 22, 24 | eqeltrd 2273 | 
. . . . 5
⊢ ((𝜑 ∧ 𝑘 ∈ 𝐵) → if(𝑘 ∈ 𝐵, 𝐶, 1) ∈ ℂ) | 
| 26 |   | fprodsplitdc.1 | 
. . . . . . . . . . . . . 14
⊢ (𝜑 → (𝐴 ∩ 𝐵) = ∅) | 
| 27 |   | disj 3499 | 
. . . . . . . . . . . . . 14
⊢ ((𝐴 ∩ 𝐵) = ∅ ↔ ∀𝑗 ∈ 𝐴 ¬ 𝑗 ∈ 𝐵) | 
| 28 | 26, 27 | sylib 122 | 
. . . . . . . . . . . . 13
⊢ (𝜑 → ∀𝑗 ∈ 𝐴 ¬ 𝑗 ∈ 𝐵) | 
| 29 | 28 | ad2antrr 488 | 
. . . . . . . . . . . 12
⊢ (((𝜑 ∧ 𝑗 ∈ 𝑈) ∧ DECID 𝑗 ∈ 𝐴) → ∀𝑗 ∈ 𝐴 ¬ 𝑗 ∈ 𝐵) | 
| 30 | 29 | r19.21bi 2585 | 
. . . . . . . . . . 11
⊢ ((((𝜑 ∧ 𝑗 ∈ 𝑈) ∧ DECID 𝑗 ∈ 𝐴) ∧ 𝑗 ∈ 𝐴) → ¬ 𝑗 ∈ 𝐵) | 
| 31 | 30 | olcd 735 | 
. . . . . . . . . 10
⊢ ((((𝜑 ∧ 𝑗 ∈ 𝑈) ∧ DECID 𝑗 ∈ 𝐴) ∧ 𝑗 ∈ 𝐴) → (𝑗 ∈ 𝐵 ∨ ¬ 𝑗 ∈ 𝐵)) | 
| 32 |   | df-dc 836 | 
. . . . . . . . . 10
⊢
(DECID 𝑗 ∈ 𝐵 ↔ (𝑗 ∈ 𝐵 ∨ ¬ 𝑗 ∈ 𝐵)) | 
| 33 | 31, 32 | sylibr 134 | 
. . . . . . . . 9
⊢ ((((𝜑 ∧ 𝑗 ∈ 𝑈) ∧ DECID 𝑗 ∈ 𝐴) ∧ 𝑗 ∈ 𝐴) → DECID 𝑗 ∈ 𝐵) | 
| 34 |   | simpr 110 | 
. . . . . . . . . . . 12
⊢ ((((𝜑 ∧ 𝑗 ∈ 𝑈) ∧ DECID 𝑗 ∈ 𝐴) ∧ ¬ 𝑗 ∈ 𝐴) → ¬ 𝑗 ∈ 𝐴) | 
| 35 |   | simpllr 534 | 
. . . . . . . . . . . . . . 15
⊢ ((((𝜑 ∧ 𝑗 ∈ 𝑈) ∧ DECID 𝑗 ∈ 𝐴) ∧ ¬ 𝑗 ∈ 𝐴) → 𝑗 ∈ 𝑈) | 
| 36 | 4 | eleq2d 2266 | 
. . . . . . . . . . . . . . . 16
⊢ (𝜑 → (𝑗 ∈ 𝑈 ↔ 𝑗 ∈ (𝐴 ∪ 𝐵))) | 
| 37 | 36 | ad3antrrr 492 | 
. . . . . . . . . . . . . . 15
⊢ ((((𝜑 ∧ 𝑗 ∈ 𝑈) ∧ DECID 𝑗 ∈ 𝐴) ∧ ¬ 𝑗 ∈ 𝐴) → (𝑗 ∈ 𝑈 ↔ 𝑗 ∈ (𝐴 ∪ 𝐵))) | 
| 38 | 35, 37 | mpbid 147 | 
. . . . . . . . . . . . . 14
⊢ ((((𝜑 ∧ 𝑗 ∈ 𝑈) ∧ DECID 𝑗 ∈ 𝐴) ∧ ¬ 𝑗 ∈ 𝐴) → 𝑗 ∈ (𝐴 ∪ 𝐵)) | 
| 39 |   | elun 3304 | 
. . . . . . . . . . . . . 14
⊢ (𝑗 ∈ (𝐴 ∪ 𝐵) ↔ (𝑗 ∈ 𝐴 ∨ 𝑗 ∈ 𝐵)) | 
| 40 | 38, 39 | sylib 122 | 
. . . . . . . . . . . . 13
⊢ ((((𝜑 ∧ 𝑗 ∈ 𝑈) ∧ DECID 𝑗 ∈ 𝐴) ∧ ¬ 𝑗 ∈ 𝐴) → (𝑗 ∈ 𝐴 ∨ 𝑗 ∈ 𝐵)) | 
| 41 | 40 | orcomd 730 | 
. . . . . . . . . . . 12
⊢ ((((𝜑 ∧ 𝑗 ∈ 𝑈) ∧ DECID 𝑗 ∈ 𝐴) ∧ ¬ 𝑗 ∈ 𝐴) → (𝑗 ∈ 𝐵 ∨ 𝑗 ∈ 𝐴)) | 
| 42 | 34, 41 | ecased 1360 | 
. . . . . . . . . . 11
⊢ ((((𝜑 ∧ 𝑗 ∈ 𝑈) ∧ DECID 𝑗 ∈ 𝐴) ∧ ¬ 𝑗 ∈ 𝐴) → 𝑗 ∈ 𝐵) | 
| 43 | 42 | orcd 734 | 
. . . . . . . . . 10
⊢ ((((𝜑 ∧ 𝑗 ∈ 𝑈) ∧ DECID 𝑗 ∈ 𝐴) ∧ ¬ 𝑗 ∈ 𝐴) → (𝑗 ∈ 𝐵 ∨ ¬ 𝑗 ∈ 𝐵)) | 
| 44 | 43, 32 | sylibr 134 | 
. . . . . . . . 9
⊢ ((((𝜑 ∧ 𝑗 ∈ 𝑈) ∧ DECID 𝑗 ∈ 𝐴) ∧ ¬ 𝑗 ∈ 𝐴) → DECID 𝑗 ∈ 𝐵) | 
| 45 |   | exmiddc 837 | 
. . . . . . . . . 10
⊢
(DECID 𝑗 ∈ 𝐴 → (𝑗 ∈ 𝐴 ∨ ¬ 𝑗 ∈ 𝐴)) | 
| 46 | 45 | adantl 277 | 
. . . . . . . . 9
⊢ (((𝜑 ∧ 𝑗 ∈ 𝑈) ∧ DECID 𝑗 ∈ 𝐴) → (𝑗 ∈ 𝐴 ∨ ¬ 𝑗 ∈ 𝐴)) | 
| 47 | 33, 44, 46 | mpjaodan 799 | 
. . . . . . . 8
⊢ (((𝜑 ∧ 𝑗 ∈ 𝑈) ∧ DECID 𝑗 ∈ 𝐴) → DECID 𝑗 ∈ 𝐵) | 
| 48 | 47 | ex 115 | 
. . . . . . 7
⊢ ((𝜑 ∧ 𝑗 ∈ 𝑈) → (DECID 𝑗 ∈ 𝐴 → DECID 𝑗 ∈ 𝐵)) | 
| 49 | 48 | ralimdva 2564 | 
. . . . . 6
⊢ (𝜑 → (∀𝑗 ∈ 𝑈 DECID 𝑗 ∈ 𝐴 → ∀𝑗 ∈ 𝑈 DECID 𝑗 ∈ 𝐵)) | 
| 50 | 11, 49 | mpd 13 | 
. . . . 5
⊢ (𝜑 → ∀𝑗 ∈ 𝑈 DECID 𝑗 ∈ 𝐵) | 
| 51 |   | eldifn 3286 | 
. . . . . . 7
⊢ (𝑘 ∈ (𝑈 ∖ 𝐵) → ¬ 𝑘 ∈ 𝐵) | 
| 52 | 51 | iffalsed 3571 | 
. . . . . 6
⊢ (𝑘 ∈ (𝑈 ∖ 𝐵) → if(𝑘 ∈ 𝐵, 𝐶, 1) = 1) | 
| 53 | 52 | adantl 277 | 
. . . . 5
⊢ ((𝜑 ∧ 𝑘 ∈ (𝑈 ∖ 𝐵)) → if(𝑘 ∈ 𝐵, 𝐶, 1) = 1) | 
| 54 | 21, 25, 50, 53, 15 | fprodssdc 11755 | 
. . . 4
⊢ (𝜑 → ∏𝑘 ∈ 𝐵 if(𝑘 ∈ 𝐵, 𝐶, 1) = ∏𝑘 ∈ 𝑈 if(𝑘 ∈ 𝐵, 𝐶, 1)) | 
| 55 | 19, 54 | eqtr3id 2243 | 
. . 3
⊢ (𝜑 → ∏𝑘 ∈ 𝐵 𝐶 = ∏𝑘 ∈ 𝑈 if(𝑘 ∈ 𝐵, 𝐶, 1)) | 
| 56 | 17, 55 | oveq12d 5940 | 
. 2
⊢ (𝜑 → (∏𝑘 ∈ 𝐴 𝐶 · ∏𝑘 ∈ 𝐵 𝐶) = (∏𝑘 ∈ 𝑈 if(𝑘 ∈ 𝐴, 𝐶, 1) · ∏𝑘 ∈ 𝑈 if(𝑘 ∈ 𝐵, 𝐶, 1))) | 
| 57 |   | 1cnd 8042 | 
. . . 4
⊢ ((𝜑 ∧ 𝑘 ∈ 𝑈) → 1 ∈ ℂ) | 
| 58 |   | eleq1w 2257 | 
. . . . . . . 8
⊢ (𝑗 = 𝑘 → (𝑗 ∈ 𝐴 ↔ 𝑘 ∈ 𝐴)) | 
| 59 | 58 | dcbid 839 | 
. . . . . . 7
⊢ (𝑗 = 𝑘 → (DECID 𝑗 ∈ 𝐴 ↔ DECID 𝑘 ∈ 𝐴)) | 
| 60 | 59 | cbvralv 2729 | 
. . . . . 6
⊢
(∀𝑗 ∈
𝑈 DECID
𝑗 ∈ 𝐴 ↔ ∀𝑘 ∈ 𝑈 DECID 𝑘 ∈ 𝐴) | 
| 61 | 11, 60 | sylib 122 | 
. . . . 5
⊢ (𝜑 → ∀𝑘 ∈ 𝑈 DECID 𝑘 ∈ 𝐴) | 
| 62 | 61 | r19.21bi 2585 | 
. . . 4
⊢ ((𝜑 ∧ 𝑘 ∈ 𝑈) → DECID 𝑘 ∈ 𝐴) | 
| 63 | 8, 57, 62 | ifcldcd 3597 | 
. . 3
⊢ ((𝜑 ∧ 𝑘 ∈ 𝑈) → if(𝑘 ∈ 𝐴, 𝐶, 1) ∈ ℂ) | 
| 64 |   | eleq1w 2257 | 
. . . . . . . 8
⊢ (𝑗 = 𝑘 → (𝑗 ∈ 𝐵 ↔ 𝑘 ∈ 𝐵)) | 
| 65 | 64 | dcbid 839 | 
. . . . . . 7
⊢ (𝑗 = 𝑘 → (DECID 𝑗 ∈ 𝐵 ↔ DECID 𝑘 ∈ 𝐵)) | 
| 66 | 65 | cbvralv 2729 | 
. . . . . 6
⊢
(∀𝑗 ∈
𝑈 DECID
𝑗 ∈ 𝐵 ↔ ∀𝑘 ∈ 𝑈 DECID 𝑘 ∈ 𝐵) | 
| 67 | 50, 66 | sylib 122 | 
. . . . 5
⊢ (𝜑 → ∀𝑘 ∈ 𝑈 DECID 𝑘 ∈ 𝐵) | 
| 68 | 67 | r19.21bi 2585 | 
. . . 4
⊢ ((𝜑 ∧ 𝑘 ∈ 𝑈) → DECID 𝑘 ∈ 𝐵) | 
| 69 | 8, 57, 68 | ifcldcd 3597 | 
. . 3
⊢ ((𝜑 ∧ 𝑘 ∈ 𝑈) → if(𝑘 ∈ 𝐵, 𝐶, 1) ∈ ℂ) | 
| 70 | 15, 63, 69 | fprodmul 11756 | 
. 2
⊢ (𝜑 → ∏𝑘 ∈ 𝑈 (if(𝑘 ∈ 𝐴, 𝐶, 1) · if(𝑘 ∈ 𝐵, 𝐶, 1)) = (∏𝑘 ∈ 𝑈 if(𝑘 ∈ 𝐴, 𝐶, 1) · ∏𝑘 ∈ 𝑈 if(𝑘 ∈ 𝐵, 𝐶, 1))) | 
| 71 | 4 | eleq2d 2266 | 
. . . . . 6
⊢ (𝜑 → (𝑘 ∈ 𝑈 ↔ 𝑘 ∈ (𝐴 ∪ 𝐵))) | 
| 72 |   | elun 3304 | 
. . . . . 6
⊢ (𝑘 ∈ (𝐴 ∪ 𝐵) ↔ (𝑘 ∈ 𝐴 ∨ 𝑘 ∈ 𝐵)) | 
| 73 | 71, 72 | bitrdi 196 | 
. . . . 5
⊢ (𝜑 → (𝑘 ∈ 𝑈 ↔ (𝑘 ∈ 𝐴 ∨ 𝑘 ∈ 𝐵))) | 
| 74 | 73 | biimpa 296 | 
. . . 4
⊢ ((𝜑 ∧ 𝑘 ∈ 𝑈) → (𝑘 ∈ 𝐴 ∨ 𝑘 ∈ 𝐵)) | 
| 75 |   | disjel 3505 | 
. . . . . . . . 9
⊢ (((𝐴 ∩ 𝐵) = ∅ ∧ 𝑘 ∈ 𝐴) → ¬ 𝑘 ∈ 𝐵) | 
| 76 | 26, 75 | sylan 283 | 
. . . . . . . 8
⊢ ((𝜑 ∧ 𝑘 ∈ 𝐴) → ¬ 𝑘 ∈ 𝐵) | 
| 77 | 76 | iffalsed 3571 | 
. . . . . . 7
⊢ ((𝜑 ∧ 𝑘 ∈ 𝐴) → if(𝑘 ∈ 𝐵, 𝐶, 1) = 1) | 
| 78 | 6, 77 | oveq12d 5940 | 
. . . . . 6
⊢ ((𝜑 ∧ 𝑘 ∈ 𝐴) → (if(𝑘 ∈ 𝐴, 𝐶, 1) · if(𝑘 ∈ 𝐵, 𝐶, 1)) = (𝐶 · 1)) | 
| 79 | 9 | mulridd 8043 | 
. . . . . 6
⊢ ((𝜑 ∧ 𝑘 ∈ 𝐴) → (𝐶 · 1) = 𝐶) | 
| 80 | 78, 79 | eqtrd 2229 | 
. . . . 5
⊢ ((𝜑 ∧ 𝑘 ∈ 𝐴) → (if(𝑘 ∈ 𝐴, 𝐶, 1) · if(𝑘 ∈ 𝐵, 𝐶, 1)) = 𝐶) | 
| 81 | 76 | ex 115 | 
. . . . . . . . . 10
⊢ (𝜑 → (𝑘 ∈ 𝐴 → ¬ 𝑘 ∈ 𝐵)) | 
| 82 | 81 | con2d 625 | 
. . . . . . . . 9
⊢ (𝜑 → (𝑘 ∈ 𝐵 → ¬ 𝑘 ∈ 𝐴)) | 
| 83 | 82 | imp 124 | 
. . . . . . . 8
⊢ ((𝜑 ∧ 𝑘 ∈ 𝐵) → ¬ 𝑘 ∈ 𝐴) | 
| 84 | 83 | iffalsed 3571 | 
. . . . . . 7
⊢ ((𝜑 ∧ 𝑘 ∈ 𝐵) → if(𝑘 ∈ 𝐴, 𝐶, 1) = 1) | 
| 85 | 84, 22 | oveq12d 5940 | 
. . . . . 6
⊢ ((𝜑 ∧ 𝑘 ∈ 𝐵) → (if(𝑘 ∈ 𝐴, 𝐶, 1) · if(𝑘 ∈ 𝐵, 𝐶, 1)) = (1 · 𝐶)) | 
| 86 | 24 | mulid2d 8045 | 
. . . . . 6
⊢ ((𝜑 ∧ 𝑘 ∈ 𝐵) → (1 · 𝐶) = 𝐶) | 
| 87 | 85, 86 | eqtrd 2229 | 
. . . . 5
⊢ ((𝜑 ∧ 𝑘 ∈ 𝐵) → (if(𝑘 ∈ 𝐴, 𝐶, 1) · if(𝑘 ∈ 𝐵, 𝐶, 1)) = 𝐶) | 
| 88 | 80, 87 | jaodan 798 | 
. . . 4
⊢ ((𝜑 ∧ (𝑘 ∈ 𝐴 ∨ 𝑘 ∈ 𝐵)) → (if(𝑘 ∈ 𝐴, 𝐶, 1) · if(𝑘 ∈ 𝐵, 𝐶, 1)) = 𝐶) | 
| 89 | 74, 88 | syldan 282 | 
. . 3
⊢ ((𝜑 ∧ 𝑘 ∈ 𝑈) → (if(𝑘 ∈ 𝐴, 𝐶, 1) · if(𝑘 ∈ 𝐵, 𝐶, 1)) = 𝐶) | 
| 90 | 89 | prodeq2dv 11731 | 
. 2
⊢ (𝜑 → ∏𝑘 ∈ 𝑈 (if(𝑘 ∈ 𝐴, 𝐶, 1) · if(𝑘 ∈ 𝐵, 𝐶, 1)) = ∏𝑘 ∈ 𝑈 𝐶) | 
| 91 | 56, 70, 90 | 3eqtr2rd 2236 | 
1
⊢ (𝜑 → ∏𝑘 ∈ 𝑈 𝐶 = (∏𝑘 ∈ 𝐴 𝐶 · ∏𝑘 ∈ 𝐵 𝐶)) |