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Theorem cnvcnvss 4775
Description: The double converse of a class is a subclass. Exercise 2 of [TakeutiZaring] p. 25. (Contributed by NM, 23-Jul-2004.)
Assertion
Ref Expression
cnvcnvss  |-  `' `' A  C_  A

Proof of Theorem cnvcnvss
StepHypRef Expression
1 cnvcnv 4773 . 2  |-  `' `' A  =  ( A  i^i  ( _V  X.  _V ) )
2 inss1 3157 . 2  |-  ( A  i^i  ( _V  X.  _V ) )  C_  A
31, 2eqsstri 2975 1  |-  `' `' A  C_  A
Colors of variables: wff set class
Syntax hints:   _Vcvv 2557    i^i cin 2916    C_ wss 2917    X. cxp 4343   `'ccnv 4344
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 630  ax-5 1336  ax-7 1337  ax-gen 1338  ax-ie1 1382  ax-ie2 1383  ax-8 1395  ax-10 1396  ax-11 1397  ax-i12 1398  ax-bndl 1399  ax-4 1400  ax-14 1405  ax-17 1419  ax-i9 1423  ax-ial 1427  ax-i5r 1428  ax-ext 2022  ax-sep 3875  ax-pow 3927  ax-pr 3944
This theorem depends on definitions:  df-bi 110  df-3an 887  df-tru 1246  df-nf 1350  df-sb 1646  df-eu 1903  df-mo 1904  df-clab 2027  df-cleq 2033  df-clel 2036  df-nfc 2167  df-ral 2311  df-rex 2312  df-v 2559  df-un 2922  df-in 2924  df-ss 2931  df-pw 3361  df-sn 3381  df-pr 3382  df-op 3384  df-br 3765  df-opab 3819  df-xp 4351  df-rel 4352  df-cnv 4353
This theorem is referenced by:  funcnvcnv  4958  foimacnv  5144
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