Theorem cbvrex2vw 3246

Description: Change bound variables of double restricted universal quantification, using implicit substitution. Version of cbvrex2v 3355 with a disjoint variable condition, which does not require ax-13 2402. (Contributed by FL, 2-Jul-2012.) Avoid ax-13 2402. (Revised by GG, 10-Jan-2024.)

Hypotheses

Ref	Expression
cbvrex2vw.1	⊢ (𝑥 = 𝑧 → (𝜑 ↔ 𝜒))
cbvrex2vw.2	⊢ (𝑦 = 𝑤 → (𝜒 ↔ 𝜓))

Assertion

Ref	Expression
cbvrex2vw	⊢ (∃𝑥 ∈ 𝐴 ∃𝑦 ∈ 𝐵 𝜑 ↔ ∃𝑧 ∈ 𝐴 ∃𝑤 ∈ 𝐵 𝜓)

Distinct variable groups:   𝑥,𝑧   𝑦,𝑤   𝑥,𝐴,𝑧   𝑤,𝐵   𝑥,𝐵,𝑦,𝑧   𝜒,𝑤   𝜒,𝑥   𝜑,𝑧   𝜓,𝑦

Allowed substitution hints:   𝜑(𝑥, 𝑦, 𝑤)   𝜓(𝑥, 𝑧, 𝑤)   𝜒(𝑦, 𝑧)   𝐴(𝑦, 𝑤)

Proof of Theorem cbvrex2vw

Step	Hyp	Ref	Expression
1		cbvrex2vw.1	. . . 4 ⊢ (𝑥 = 𝑧 → (𝜑 ↔ 𝜒))
2	1	rexbidv 3187	. . 3 ⊢ (𝑥 = 𝑧 → (∃𝑦 ∈ 𝐵 𝜑 ↔ ∃𝑦 ∈ 𝐵 𝜒))
3	2	cbvrexvw 3242	. 2 ⊢ (∃𝑥 ∈ 𝐴 ∃𝑦 ∈ 𝐵 𝜑 ↔ ∃𝑧 ∈ 𝐴 ∃𝑦 ∈ 𝐵 𝜒)
4		cbvrex2vw.2	. . . 4 ⊢ (𝑦 = 𝑤 → (𝜒 ↔ 𝜓))
5	4	cbvrexvw 3242	. . 3 ⊢ (∃𝑦 ∈ 𝐵 𝜒 ↔ ∃𝑤 ∈ 𝐵 𝜓)
6	5	rexbii 3110	. 2 ⊢ (∃𝑧 ∈ 𝐴 ∃𝑦 ∈ 𝐵 𝜒 ↔ ∃𝑧 ∈ 𝐴 ∃𝑤 ∈ 𝐵 𝜓)
7	3, 6	bitri 278	1 ⊢ (∃𝑥 ∈ 𝐴 ∃𝑦 ∈ 𝐵 𝜑 ↔ ∃𝑧 ∈ 𝐴 ∃𝑤 ∈ 𝐵 𝜓)

This proof depends on syntax axioms:   → wi 4   ↔ wb 209  ∃wrex 3087

This proof depends on axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-3 8  ax-gen 1828  ax-4 1842  ax-5 1943  ax-6 2000  ax-7 2041  ax-8 2147

This proof depends on definitions:  df-bi 210  df-an 402  df-ex 1813  df-clel 2836  df-rex 3088

This theorem is used by:  omeu  8586  oeeui  8604  eroveu  8826  genpv  11077  bezoutlem3  16707  bezoutlem4  16708  bezout  16709  4sqlem2  17120  vdwnn  17169  efgrelexlema  19956  dyadmax  25912  2sqlem9  27747  2sq  27750  nna4b4nsq  27983  mulsval2lem  28489  mulsunif2  28549  precsexlemcbv  28585  eucliddivs  28755  bdayfinbndcbv  28845  bdayfinbndlem1  28846  bdayfinbndlem2  28847  z12zsodd  28861  legov  29041  dfcgra2  29331  gsumwun  33630  constrcbvlem  34380  pstmfval  34521  satfv0  36102  satfv0fun  36115  fmla1  36131  nn0prpwlem  37090  isbnd2  38697  hashnexinjle  43159  aks6d1c6lem3  43202  oaun3lem1  44360  limsupref  46664  fourierdlem42  47128  fourierdlem54  47139  mogoldbb  48852