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Theorem csbeq1a 3144
 Description: Equality theorem for proper substitution into a class. (Contributed by NM, 10-Nov-2005.)
Assertion
Ref Expression
csbeq1a (x = AB = [A / x]B)

Proof of Theorem csbeq1a
StepHypRef Expression
1 csbid 3143 . 2 [x / x]B = B
2 csbeq1 3139 . 2 (x = A[x / x]B = [A / x]B)
31, 2syl5eqr 2399 1 (x = AB = [A / x]B)
 Colors of variables: wff setvar class Syntax hints:   → wi 4   = wceq 1642  [csb 3136 This theorem was proved from axioms:  ax-1 5  ax-2 6  ax-3 7  ax-mp 8  ax-gen 1546  ax-5 1557  ax-17 1616  ax-9 1654  ax-8 1675  ax-6 1729  ax-7 1734  ax-11 1746  ax-12 1925  ax-ext 2334 This theorem depends on definitions:  df-bi 177  df-an 360  df-tru 1319  df-ex 1542  df-nf 1545  df-sb 1649  df-clab 2340  df-cleq 2346  df-clel 2349  df-sbc 3047  df-csb 3137 This theorem is referenced by:  csbhypf  3171  csbiebt  3172  sbcnestgf  3183  cbvralcsf  3198  cbvreucsf  3200  cbvrabcsf  3201  csbing  3462  csbifg  3690  sbcbrg  4685  opeliunxp  4820  csbima12g  4955  csbovg  5552  fvmpts  5701  fvmpt2i  5703  fvmptex  5721  fmpt2x  5730
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