Theorem elndif 4078

Description: A set does not belong to a class excluding it. (Contributed by NM, 27-Jun-1994.)

Assertion

Ref	Expression
elndif	⊢ (𝐴 ∈ 𝐵 → ¬ 𝐴 ∈ (𝐶 ∖ 𝐵))

Proof of Theorem elndif

Step	Hyp	Ref	Expression
1		eldifn 4077	. 2 ⊢ (𝐴 ∈ (𝐶 ∖ 𝐵) → ¬ 𝐴 ∈ 𝐵)
2	1	con2i 139	1 ⊢ (𝐴 ∈ 𝐵 → ¬ 𝐴 ∈ (𝐶 ∖ 𝐵))

Syntax hints:  ¬ wn 3   → wi 4   ∈ wcel 2111   ∖ cdif 3894

This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-3 8  ax-gen 1796  ax-4 1810  ax-5 1911  ax-6 1968  ax-7 2009  ax-8 2113  ax-9 2121  ax-ext 2703

This theorem depends on definitions:  df-bi 207  df-an 396  df-tru 1544  df-ex 1781  df-sb 2068  df-clab 2710  df-cleq 2723  df-clel 2806  df-v 3438  df-dif 3900

This theorem is referenced by:  peano5  7818  extmptsuppeq  8113  undifixp  8853  ssfin4  10196  isf32lem3  10241  isf34lem4  10263  xrinfmss  13204  restntr  23092  cmpcld  23312  reconnlem2  24738  lebnumlem1  24882  i1fd  25604  ssdifidlprm  33415  hgt750lemd  34653  fmlasucdisj  35435  dfon2lem6  35822  onsucconni  36471  meaiininclem  46524  caragendifcl  46552