Theorem prodex 15847

Description: A product is a set. (Contributed by Scott Fenton, 4-Dec-2017.)

Assertion

Ref	Expression
prodex	⊢ ∏𝑘 ∈ 𝐴 𝐵 ∈ V

Proof of Theorem prodex

Dummy variables 𝑓 𝑚 𝑛 𝑥 𝑦 are mutually distinct and distinct from all other variables.

Step	Hyp	Ref	Expression
1		df-prod 15846	. 2 ⊢ ∏𝑘 ∈ 𝐴 𝐵 = (℩𝑥(∃𝑚 ∈ ℤ (𝐴 ⊆ (ℤ≥‘𝑚) ∧ ∃𝑛 ∈ (ℤ≥‘𝑚)∃𝑦(𝑦 ≠ 0 ∧ seq𝑛( · , (𝑘 ∈ ℤ ↦ if(𝑘 ∈ 𝐴, 𝐵, 1))) ⇝ 𝑦) ∧ seq𝑚( · , (𝑘 ∈ ℤ ↦ if(𝑘 ∈ 𝐴, 𝐵, 1))) ⇝ 𝑥) ∨ ∃𝑚 ∈ ℕ ∃𝑓(𝑓:(1...𝑚)–1-1-onto→𝐴 ∧ 𝑥 = (seq1( · , (𝑛 ∈ ℕ ↦ ⦋(𝑓‘𝑛) / 𝑘⦌𝐵))‘𝑚))))
2		iotaex 6472	. 2 ⊢ (℩𝑥(∃𝑚 ∈ ℤ (𝐴 ⊆ (ℤ≥‘𝑚) ∧ ∃𝑛 ∈ (ℤ≥‘𝑚)∃𝑦(𝑦 ≠ 0 ∧ seq𝑛( · , (𝑘 ∈ ℤ ↦ if(𝑘 ∈ 𝐴, 𝐵, 1))) ⇝ 𝑦) ∧ seq𝑚( · , (𝑘 ∈ ℤ ↦ if(𝑘 ∈ 𝐴, 𝐵, 1))) ⇝ 𝑥) ∨ ∃𝑚 ∈ ℕ ∃𝑓(𝑓:(1...𝑚)–1-1-onto→𝐴 ∧ 𝑥 = (seq1( · , (𝑛 ∈ ℕ ↦ ⦋(𝑓‘𝑛) / 𝑘⦌𝐵))‘𝑚)))) ∈ V
3	1, 2	eqeltri 2824	1 ⊢ ∏𝑘 ∈ 𝐴 𝐵 ∈ V

Syntax hints:   ∧ wa 395   ∨ wo 847   ∧ w3a 1086   = wceq 1540  ∃wex 1779   ∈ wcel 2109   ≠ wne 2925  ∃wrex 3053  Vcvv 3444  ⦋csb 3859   ⊆ wss 3911  ifcif 4484   class class class wbr 5102   ↦ cmpt 5183  ℩cio 6450  –1-1-onto→wf1o 6498  ‘cfv 6499  (class class class)co 7369  0cc0 11044  1c1 11045   · cmul 11049  ℕcn 12162  ℤcz 12505  ℤ_≥cuz 12769  ...cfz 13444  seqcseq 13942   ⇝ cli 15426  ∏cprod 15845

This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-3 8  ax-gen 1795  ax-4 1809  ax-5 1910  ax-6 1967  ax-7 2008  ax-8 2111  ax-9 2119  ax-ext 2701  ax-nul 5256

This theorem depends on definitions:  df-bi 207  df-an 396  df-or 848  df-tru 1543  df-fal 1553  df-ex 1780  df-sb 2066  df-clab 2708  df-cleq 2721  df-clel 2803  df-ne 2926  df-v 3446  df-dif 3914  df-un 3916  df-ss 3928  df-nul 4293  df-sn 4586  df-pr 4588  df-uni 4868  df-iota 6452  df-prod 15846

This theorem is referenced by:  risefacval  15950  fallfacval  15951  prmoval  16980  fprodsubrecnncnvlem  45878  fprodaddrecnncnvlem  45880  etransclem13  46218  ovnlecvr  46529  ovncvrrp  46535  hoidmvval  46548  vonioolem1  46651