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Theorem sumeq1 10807
Description: Equality theorem for a sum. (Contributed by NM, 11-Dec-2005.) (Revised by Mario Carneiro, 13-Jun-2019.)
Assertion
Ref Expression
sumeq1 (𝐴 = 𝐵 → Σ𝑘𝐴 𝐶 = Σ𝑘𝐵 𝐶)

Proof of Theorem sumeq1
Dummy variables 𝑓 𝑚 𝑛 𝑥 𝑗 are mutually distinct and distinct from all other variables.
StepHypRef Expression
1 sseq1 3050 . . . . . 6 (𝐴 = 𝐵 → (𝐴 ⊆ (ℤ𝑚) ↔ 𝐵 ⊆ (ℤ𝑚)))
2 eleq2 2152 . . . . . . . 8 (𝐴 = 𝐵 → (𝑗𝐴𝑗𝐵))
32dcbid 787 . . . . . . 7 (𝐴 = 𝐵 → (DECID 𝑗𝐴DECID 𝑗𝐵))
43ralbidv 2381 . . . . . 6 (𝐴 = 𝐵 → (∀𝑗 ∈ (ℤ𝑚)DECID 𝑗𝐴 ↔ ∀𝑗 ∈ (ℤ𝑚)DECID 𝑗𝐵))
5 simpl 108 . . . . . . . . . . 11 ((𝐴 = 𝐵𝑛 ∈ ℤ) → 𝐴 = 𝐵)
65eleq2d 2158 . . . . . . . . . 10 ((𝐴 = 𝐵𝑛 ∈ ℤ) → (𝑛𝐴𝑛𝐵))
76ifbid 3418 . . . . . . . . 9 ((𝐴 = 𝐵𝑛 ∈ ℤ) → if(𝑛𝐴, 𝑛 / 𝑘𝐶, 0) = if(𝑛𝐵, 𝑛 / 𝑘𝐶, 0))
87mpteq2dva 3936 . . . . . . . 8 (𝐴 = 𝐵 → (𝑛 ∈ ℤ ↦ if(𝑛𝐴, 𝑛 / 𝑘𝐶, 0)) = (𝑛 ∈ ℤ ↦ if(𝑛𝐵, 𝑛 / 𝑘𝐶, 0)))
9 iseqeq3 9923 . . . . . . . 8 ((𝑛 ∈ ℤ ↦ if(𝑛𝐴, 𝑛 / 𝑘𝐶, 0)) = (𝑛 ∈ ℤ ↦ if(𝑛𝐵, 𝑛 / 𝑘𝐶, 0)) → seq𝑚( + , (𝑛 ∈ ℤ ↦ if(𝑛𝐴, 𝑛 / 𝑘𝐶, 0)), ℂ) = seq𝑚( + , (𝑛 ∈ ℤ ↦ if(𝑛𝐵, 𝑛 / 𝑘𝐶, 0)), ℂ))
108, 9syl 14 . . . . . . 7 (𝐴 = 𝐵 → seq𝑚( + , (𝑛 ∈ ℤ ↦ if(𝑛𝐴, 𝑛 / 𝑘𝐶, 0)), ℂ) = seq𝑚( + , (𝑛 ∈ ℤ ↦ if(𝑛𝐵, 𝑛 / 𝑘𝐶, 0)), ℂ))
1110breq1d 3863 . . . . . 6 (𝐴 = 𝐵 → (seq𝑚( + , (𝑛 ∈ ℤ ↦ if(𝑛𝐴, 𝑛 / 𝑘𝐶, 0)), ℂ) ⇝ 𝑥 ↔ seq𝑚( + , (𝑛 ∈ ℤ ↦ if(𝑛𝐵, 𝑛 / 𝑘𝐶, 0)), ℂ) ⇝ 𝑥))
121, 4, 113anbi123d 1249 . . . . 5 (𝐴 = 𝐵 → ((𝐴 ⊆ (ℤ𝑚) ∧ ∀𝑗 ∈ (ℤ𝑚)DECID 𝑗𝐴 ∧ seq𝑚( + , (𝑛 ∈ ℤ ↦ if(𝑛𝐴, 𝑛 / 𝑘𝐶, 0)), ℂ) ⇝ 𝑥) ↔ (𝐵 ⊆ (ℤ𝑚) ∧ ∀𝑗 ∈ (ℤ𝑚)DECID 𝑗𝐵 ∧ seq𝑚( + , (𝑛 ∈ ℤ ↦ if(𝑛𝐵, 𝑛 / 𝑘𝐶, 0)), ℂ) ⇝ 𝑥)))
1312rexbidv 2382 . . . 4 (𝐴 = 𝐵 → (∃𝑚 ∈ ℤ (𝐴 ⊆ (ℤ𝑚) ∧ ∀𝑗 ∈ (ℤ𝑚)DECID 𝑗𝐴 ∧ seq𝑚( + , (𝑛 ∈ ℤ ↦ if(𝑛𝐴, 𝑛 / 𝑘𝐶, 0)), ℂ) ⇝ 𝑥) ↔ ∃𝑚 ∈ ℤ (𝐵 ⊆ (ℤ𝑚) ∧ ∀𝑗 ∈ (ℤ𝑚)DECID 𝑗𝐵 ∧ seq𝑚( + , (𝑛 ∈ ℤ ↦ if(𝑛𝐵, 𝑛 / 𝑘𝐶, 0)), ℂ) ⇝ 𝑥)))
14 f1oeq3 5261 . . . . . . 7 (𝐴 = 𝐵 → (𝑓:(1...𝑚)–1-1-onto𝐴𝑓:(1...𝑚)–1-1-onto𝐵))
1514anbi1d 454 . . . . . 6 (𝐴 = 𝐵 → ((𝑓:(1...𝑚)–1-1-onto𝐴𝑥 = (seq1( + , (𝑛 ∈ ℕ ↦ if(𝑛𝑚, (𝑓𝑛) / 𝑘𝐶, 0)), ℂ)‘𝑚)) ↔ (𝑓:(1...𝑚)–1-1-onto𝐵𝑥 = (seq1( + , (𝑛 ∈ ℕ ↦ if(𝑛𝑚, (𝑓𝑛) / 𝑘𝐶, 0)), ℂ)‘𝑚))))
1615exbidv 1754 . . . . 5 (𝐴 = 𝐵 → (∃𝑓(𝑓:(1...𝑚)–1-1-onto𝐴𝑥 = (seq1( + , (𝑛 ∈ ℕ ↦ if(𝑛𝑚, (𝑓𝑛) / 𝑘𝐶, 0)), ℂ)‘𝑚)) ↔ ∃𝑓(𝑓:(1...𝑚)–1-1-onto𝐵𝑥 = (seq1( + , (𝑛 ∈ ℕ ↦ if(𝑛𝑚, (𝑓𝑛) / 𝑘𝐶, 0)), ℂ)‘𝑚))))
1716rexbidv 2382 . . . 4 (𝐴 = 𝐵 → (∃𝑚 ∈ ℕ ∃𝑓(𝑓:(1...𝑚)–1-1-onto𝐴𝑥 = (seq1( + , (𝑛 ∈ ℕ ↦ if(𝑛𝑚, (𝑓𝑛) / 𝑘𝐶, 0)), ℂ)‘𝑚)) ↔ ∃𝑚 ∈ ℕ ∃𝑓(𝑓:(1...𝑚)–1-1-onto𝐵𝑥 = (seq1( + , (𝑛 ∈ ℕ ↦ if(𝑛𝑚, (𝑓𝑛) / 𝑘𝐶, 0)), ℂ)‘𝑚))))
1813, 17orbi12d 743 . . 3 (𝐴 = 𝐵 → ((∃𝑚 ∈ ℤ (𝐴 ⊆ (ℤ𝑚) ∧ ∀𝑗 ∈ (ℤ𝑚)DECID 𝑗𝐴 ∧ seq𝑚( + , (𝑛 ∈ ℤ ↦ if(𝑛𝐴, 𝑛 / 𝑘𝐶, 0)), ℂ) ⇝ 𝑥) ∨ ∃𝑚 ∈ ℕ ∃𝑓(𝑓:(1...𝑚)–1-1-onto𝐴𝑥 = (seq1( + , (𝑛 ∈ ℕ ↦ if(𝑛𝑚, (𝑓𝑛) / 𝑘𝐶, 0)), ℂ)‘𝑚))) ↔ (∃𝑚 ∈ ℤ (𝐵 ⊆ (ℤ𝑚) ∧ ∀𝑗 ∈ (ℤ𝑚)DECID 𝑗𝐵 ∧ seq𝑚( + , (𝑛 ∈ ℤ ↦ if(𝑛𝐵, 𝑛 / 𝑘𝐶, 0)), ℂ) ⇝ 𝑥) ∨ ∃𝑚 ∈ ℕ ∃𝑓(𝑓:(1...𝑚)–1-1-onto𝐵𝑥 = (seq1( + , (𝑛 ∈ ℕ ↦ if(𝑛𝑚, (𝑓𝑛) / 𝑘𝐶, 0)), ℂ)‘𝑚)))))
1918iotabidv 5016 . 2 (𝐴 = 𝐵 → (℩𝑥(∃𝑚 ∈ ℤ (𝐴 ⊆ (ℤ𝑚) ∧ ∀𝑗 ∈ (ℤ𝑚)DECID 𝑗𝐴 ∧ seq𝑚( + , (𝑛 ∈ ℤ ↦ if(𝑛𝐴, 𝑛 / 𝑘𝐶, 0)), ℂ) ⇝ 𝑥) ∨ ∃𝑚 ∈ ℕ ∃𝑓(𝑓:(1...𝑚)–1-1-onto𝐴𝑥 = (seq1( + , (𝑛 ∈ ℕ ↦ if(𝑛𝑚, (𝑓𝑛) / 𝑘𝐶, 0)), ℂ)‘𝑚)))) = (℩𝑥(∃𝑚 ∈ ℤ (𝐵 ⊆ (ℤ𝑚) ∧ ∀𝑗 ∈ (ℤ𝑚)DECID 𝑗𝐵 ∧ seq𝑚( + , (𝑛 ∈ ℤ ↦ if(𝑛𝐵, 𝑛 / 𝑘𝐶, 0)), ℂ) ⇝ 𝑥) ∨ ∃𝑚 ∈ ℕ ∃𝑓(𝑓:(1...𝑚)–1-1-onto𝐵𝑥 = (seq1( + , (𝑛 ∈ ℕ ↦ if(𝑛𝑚, (𝑓𝑛) / 𝑘𝐶, 0)), ℂ)‘𝑚)))))
20 df-isum 10806 . 2 Σ𝑘𝐴 𝐶 = (℩𝑥(∃𝑚 ∈ ℤ (𝐴 ⊆ (ℤ𝑚) ∧ ∀𝑗 ∈ (ℤ𝑚)DECID 𝑗𝐴 ∧ seq𝑚( + , (𝑛 ∈ ℤ ↦ if(𝑛𝐴, 𝑛 / 𝑘𝐶, 0)), ℂ) ⇝ 𝑥) ∨ ∃𝑚 ∈ ℕ ∃𝑓(𝑓:(1...𝑚)–1-1-onto𝐴𝑥 = (seq1( + , (𝑛 ∈ ℕ ↦ if(𝑛𝑚, (𝑓𝑛) / 𝑘𝐶, 0)), ℂ)‘𝑚))))
21 df-isum 10806 . 2 Σ𝑘𝐵 𝐶 = (℩𝑥(∃𝑚 ∈ ℤ (𝐵 ⊆ (ℤ𝑚) ∧ ∀𝑗 ∈ (ℤ𝑚)DECID 𝑗𝐵 ∧ seq𝑚( + , (𝑛 ∈ ℤ ↦ if(𝑛𝐵, 𝑛 / 𝑘𝐶, 0)), ℂ) ⇝ 𝑥) ∨ ∃𝑚 ∈ ℕ ∃𝑓(𝑓:(1...𝑚)–1-1-onto𝐵𝑥 = (seq1( + , (𝑛 ∈ ℕ ↦ if(𝑛𝑚, (𝑓𝑛) / 𝑘𝐶, 0)), ℂ)‘𝑚))))
2219, 20, 213eqtr4g 2146 1 (𝐴 = 𝐵 → Σ𝑘𝐴 𝐶 = Σ𝑘𝐵 𝐶)
Colors of variables: wff set class
Syntax hints:  wi 4  wa 103  wo 665  DECID wdc 781  w3a 925   = wceq 1290  wex 1427  wcel 1439  wral 2360  wrex 2361  csb 2936  wss 3002  ifcif 3399   class class class wbr 3853  cmpt 3907  cio 4993  1-1-ontowf1o 5029  cfv 5030  (class class class)co 5668  cc 7411  0cc0 7413  1c1 7414   + caddc 7416  cle 7586  cn 8485  cz 8813  cuz 9082  ...cfz 9487  seqcseq4 9914  cli 10729  Σcsu 10805
This theorem was proved from axioms:  ax-1 5  ax-2 6  ax-mp 7  ax-ia1 105  ax-ia2 106  ax-ia3 107  ax-in1 580  ax-in2 581  ax-io 666  ax-5 1382  ax-7 1383  ax-gen 1384  ax-ie1 1428  ax-ie2 1429  ax-8 1441  ax-10 1442  ax-11 1443  ax-i12 1444  ax-bndl 1445  ax-4 1446  ax-17 1465  ax-i9 1469  ax-ial 1473  ax-i5r 1474  ax-ext 2071
This theorem depends on definitions:  df-bi 116  df-dc 782  df-3an 927  df-tru 1293  df-nf 1396  df-sb 1694  df-clab 2076  df-cleq 2082  df-clel 2085  df-nfc 2218  df-ral 2365  df-rex 2366  df-v 2624  df-un 3006  df-in 3008  df-ss 3015  df-if 3400  df-sn 3458  df-pr 3459  df-op 3461  df-uni 3662  df-br 3854  df-opab 3908  df-mpt 3909  df-cnv 4462  df-dm 4464  df-rn 4465  df-res 4466  df-iota 4995  df-f 5034  df-f1 5035  df-fo 5036  df-f1o 5037  df-fv 5038  df-ov 5671  df-oprab 5672  df-mpt2 5673  df-recs 6086  df-frec 6172  df-iseq 9916  df-isum 10806
This theorem is referenced by:  sumeq1i  10815  sumeq1d  10818  isumz  10844  fsumadd  10863  fsum2d  10892  fisumrev2  10903  fsummulc2  10905  fsumconst  10911  modfsummod  10915  fsumabs  10922  fsumrelem  10928  fsumiun  10934
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