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Theorem cbvcsbw 3918
Description: Change bound variables in a class substitution. Interestingly, this does not require any bound variable conditions on 𝐴. Version of cbvcsb 3919 with a disjoint variable condition, which does not require ax-13 2375. (Contributed by Jeff Hankins, 13-Sep-2009.) Avoid ax-13 2375. (Revised by GG, 10-Jan-2024.)
Hypotheses
Ref Expression
cbvcsbw.1 𝑦𝐶
cbvcsbw.2 𝑥𝐷
cbvcsbw.3 (𝑥 = 𝑦𝐶 = 𝐷)
Assertion
Ref Expression
cbvcsbw 𝐴 / 𝑥𝐶 = 𝐴 / 𝑦𝐷
Distinct variable group:   𝑥,𝑦
Allowed substitution hints:   𝐴(𝑥,𝑦)   𝐶(𝑥,𝑦)   𝐷(𝑥,𝑦)

Proof of Theorem cbvcsbw
Dummy variable 𝑧 is distinct from all other variables.
StepHypRef Expression
1 cbvcsbw.1 . . . . 5 𝑦𝐶
21nfcri 2895 . . . 4 𝑦 𝑧𝐶
3 cbvcsbw.2 . . . . 5 𝑥𝐷
43nfcri 2895 . . . 4 𝑥 𝑧𝐷
5 cbvcsbw.3 . . . . 5 (𝑥 = 𝑦𝐶 = 𝐷)
65eleq2d 2825 . . . 4 (𝑥 = 𝑦 → (𝑧𝐶𝑧𝐷))
72, 4, 6cbvsbcw 3825 . . 3 ([𝐴 / 𝑥]𝑧𝐶[𝐴 / 𝑦]𝑧𝐷)
87abbii 2807 . 2 {𝑧[𝐴 / 𝑥]𝑧𝐶} = {𝑧[𝐴 / 𝑦]𝑧𝐷}
9 df-csb 3909 . 2 𝐴 / 𝑥𝐶 = {𝑧[𝐴 / 𝑥]𝑧𝐶}
10 df-csb 3909 . 2 𝐴 / 𝑦𝐷 = {𝑧[𝐴 / 𝑦]𝑧𝐷}
118, 9, 103eqtr4i 2773 1 𝐴 / 𝑥𝐶 = 𝐴 / 𝑦𝐷
Colors of variables: wff setvar class
Syntax hints:  wi 4   = wceq 1537  wcel 2106  {cab 2712  wnfc 2888  [wsbc 3791  csb 3908
This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-3 8  ax-gen 1792  ax-4 1806  ax-5 1908  ax-6 1965  ax-7 2005  ax-8 2108  ax-9 2116  ax-11 2155  ax-12 2175  ax-ext 2706
This theorem depends on definitions:  df-bi 207  df-an 396  df-ex 1777  df-nf 1781  df-sb 2063  df-clab 2713  df-cleq 2727  df-clel 2814  df-nfc 2890  df-sbc 3792  df-csb 3909
This theorem is referenced by:  cbvsum  15728  cbvprod  15946  measiuns  34198  poimirlem26  37633  climinf2mpt  45670  climinfmpt  45671
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