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Theorem ssnid 3395
 Description: A setvar variable is a member of its singleton (common case). (Contributed by David A. Wheeler, 8-Dec-2018.)
Assertion
Ref Expression
ssnid x {x}

Proof of Theorem ssnid
StepHypRef Expression
1 vex 2554 . 2 x V
21snid 3394 1 x {x}
 Colors of variables: wff set class Syntax hints:   ∈ wcel 1390  {csn 3367 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 629  ax-5 1333  ax-7 1334  ax-gen 1335  ax-ie1 1379  ax-ie2 1380  ax-8 1392  ax-10 1393  ax-11 1394  ax-i12 1395  ax-bnd 1396  ax-4 1397  ax-17 1416  ax-i9 1420  ax-ial 1424  ax-i5r 1425  ax-ext 2019 This theorem depends on definitions:  df-bi 110  df-tru 1245  df-nf 1347  df-sb 1643  df-clab 2024  df-cleq 2030  df-clel 2033  df-nfc 2164  df-v 2553  df-sn 3373 This theorem is referenced by:  dtruex  4237  fnressn  5292  fressnfv  5293
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