Theorem cbvrex2vw 3250

Description: Change bound variables of double restricted universal quantification, using implicit substitution. Version of cbvrex2v 3360 with a disjoint variable condition, which does not require ax-13 2406. (Contributed by FL, 2-Jul-2012.) Avoid ax-13 2406. (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 3191	. . 3 ⊢ (𝑥 = 𝑧 → (∃𝑦 ∈ 𝐵 𝜑 ↔ ∃𝑦 ∈ 𝐵 𝜒))
3	2	cbvrexvw 3246	. 2 ⊢ (∃𝑥 ∈ 𝐴 ∃𝑦 ∈ 𝐵 𝜑 ↔ ∃𝑧 ∈ 𝐴 ∃𝑦 ∈ 𝐵 𝜒)
4		cbvrex2vw.2	. . . 4 ⊢ (𝑦 = 𝑤 → (𝜒 ↔ 𝜓))
5	4	cbvrexvw 3246	. . 3 ⊢ (∃𝑦 ∈ 𝐵 𝜒 ↔ ∃𝑤 ∈ 𝐵 𝜓)
6	5	rexbii 3114	. 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 3091

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 2148

This proof depends on definitions:  df-bi 210  df-an 402  df-ex 1813  df-clel 2840  df-rex 3092

This theorem is used by:  omeu  8576  oeeui  8594  eroveu  8816  genpv  10999  bezoutlem3  16621  bezoutlem4  16622  bezout  16623  4sqlem2  17031  vdwnn  17080  efgrelexlema  19863  dyadmax  25808  2sqlem9  27642  2sq  27645  mulsval2lem  28354  mulsunif2  28414  precsexlemcbv  28450  eucliddivs  28620  bdayfinbndcbv  28710  bdayfinbndlem1  28711  bdayfinbndlem2  28712  z12zsodd  28726  legov  28905  dfcgra2  29192  gsumwun  33460  constrcbvlem  34209  pstmfval  34350  satfv0  35887  satfv0fun  35900  fmla1  35916  nn0prpwlem  36890  isbnd2  38492  hashnexinjle  42954  aks6d1c6lem3  42997  nna4b4nsq  43450  oaun3lem1  44159  limsupref  46457  fourierdlem42  46921  fourierdlem54  46932  mogoldbb  48608