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Theorem sbceqg 2843
Description: Distribute proper substitution through an equality relation. (Contributed by NM, 10-Nov-2005.) (Proof shortened by Andrew Salmon, 29-Jun-2011.)
Assertion
Ref Expression
sbceqg (A 𝑉 → ([A / x]B = 𝐶A / xB = A / x𝐶))

Proof of Theorem sbceqg
Dummy variables y z are mutually distinct and distinct from all other variables.
StepHypRef Expression
1 dfsbcq2 2744 . . 3 (z = A → ([z / x]B = 𝐶[A / x]B = 𝐶))
2 dfsbcq2 2744 . . . . 5 (z = A → ([z / x]y B[A / x]y B))
32abbidv 2137 . . . 4 (z = A → {y ∣ [z / x]y B} = {y[A / x]y B})
4 dfsbcq2 2744 . . . . 5 (z = A → ([z / x]y 𝐶[A / x]y 𝐶))
54abbidv 2137 . . . 4 (z = A → {y ∣ [z / x]y 𝐶} = {y[A / x]y 𝐶})
63, 5eqeq12d 2036 . . 3 (z = A → ({y ∣ [z / x]y B} = {y ∣ [z / x]y 𝐶} ↔ {y[A / x]y B} = {y[A / x]y 𝐶}))
7 nfs1v 1797 . . . . . 6 x[z / x]y B
87nfab 2164 . . . . 5 x{y ∣ [z / x]y B}
9 nfs1v 1797 . . . . . 6 x[z / x]y 𝐶
109nfab 2164 . . . . 5 x{y ∣ [z / x]y 𝐶}
118, 10nfeq 2167 . . . 4 x{y ∣ [z / x]y B} = {y ∣ [z / x]y 𝐶}
12 sbab 2146 . . . . 5 (x = zB = {y ∣ [z / x]y B})
13 sbab 2146 . . . . 5 (x = z𝐶 = {y ∣ [z / x]y 𝐶})
1412, 13eqeq12d 2036 . . . 4 (x = z → (B = 𝐶 ↔ {y ∣ [z / x]y B} = {y ∣ [z / x]y 𝐶}))
1511, 14sbie 1656 . . 3 ([z / x]B = 𝐶 ↔ {y ∣ [z / x]y B} = {y ∣ [z / x]y 𝐶})
161, 6, 15vtoclbg 2591 . 2 (A 𝑉 → ([A / x]B = 𝐶 ↔ {y[A / x]y B} = {y[A / x]y 𝐶}))
17 df-csb 2830 . . 3 A / xB = {y[A / x]y B}
18 df-csb 2830 . . 3 A / x𝐶 = {y[A / x]y 𝐶}
1917, 18eqeq12i 2035 . 2 (A / xB = A / x𝐶 ↔ {y[A / x]y B} = {y[A / x]y 𝐶})
2016, 19syl6bbr 187 1 (A 𝑉 → ([A / x]B = 𝐶A / xB = A / x𝐶))
Colors of variables: wff set class
Syntax hints:  wi 4  wb 98   = wceq 1228   wcel 1374  [wsb 1627  {cab 2008  [wsbc 2741  csb 2829
This theorem was proved from axioms:  ax-1 5  ax-2 6  ax-mp 7  ax-ia1 99  ax-ia2 100  ax-ia3 101  ax-io 617  ax-5 1316  ax-7 1317  ax-gen 1318  ax-ie1 1363  ax-ie2 1364  ax-8 1376  ax-10 1377  ax-11 1378  ax-i12 1379  ax-bnd 1380  ax-4 1381  ax-17 1400  ax-i9 1404  ax-ial 1409  ax-i5r 1410  ax-ext 2004
This theorem depends on definitions:  df-bi 110  df-tru 1231  df-nf 1330  df-sb 1628  df-clab 2009  df-cleq 2015  df-clel 2018  df-nfc 2149  df-v 2537  df-sbc 2742  df-csb 2830
This theorem is referenced by:  sbcne12g  2845  sbceq1g  2847  sbceq2g  2849  sbcfng  4970
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