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Theorem difprsn2 4804
Description: Removal of a singleton from an unordered pair. (Contributed by Alexander van der Vekens, 5-Oct-2017.)
Assertion
Ref Expression
difprsn2 (𝐴𝐵 → ({𝐴, 𝐵} ∖ {𝐵}) = {𝐴})

Proof of Theorem difprsn2
StepHypRef Expression
1 prcom 4736 . . 3 {𝐴, 𝐵} = {𝐵, 𝐴}
21difeq1i 4118 . 2 ({𝐴, 𝐵} ∖ {𝐵}) = ({𝐵, 𝐴} ∖ {𝐵})
3 necom 2994 . . 3 (𝐴𝐵𝐵𝐴)
4 difprsn1 4803 . . 3 (𝐵𝐴 → ({𝐵, 𝐴} ∖ {𝐵}) = {𝐴})
53, 4sylbi 216 . 2 (𝐴𝐵 → ({𝐵, 𝐴} ∖ {𝐵}) = {𝐴})
62, 5eqtrid 2784 1 (𝐴𝐵 → ({𝐴, 𝐵} ∖ {𝐵}) = {𝐴})
Colors of variables: wff setvar class
Syntax hints:  wi 4   = wceq 1541  wne 2940  cdif 3945  {csn 4628  {cpr 4630
This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-3 8  ax-gen 1797  ax-4 1811  ax-5 1913  ax-6 1971  ax-7 2011  ax-8 2108  ax-9 2116  ax-ext 2703
This theorem depends on definitions:  df-bi 206  df-an 397  df-or 846  df-tru 1544  df-fal 1554  df-ex 1782  df-sb 2068  df-clab 2710  df-cleq 2724  df-clel 2810  df-ne 2941  df-ral 3062  df-rab 3433  df-v 3476  df-dif 3951  df-un 3953  df-in 3955  df-nul 4323  df-sn 4629  df-pr 4631
This theorem is referenced by:  f12dfv  7270  pmtrprfval  19354  nbgr2vtx1edg  28604  nbuhgr2vtx1edgb  28606  nfrgr2v  29522  cycpm2tr  32273  drngmxidl  32588  ldepsnlinc  47179
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