Theorem elndif 4092

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 4091	. 2 ⊢ (𝐴 ∈ (𝐶 ∖ 𝐵) → ¬ 𝐴 ∈ 𝐵)
2	1	con2i 139	1 ⊢ (𝐴 ∈ 𝐵 → ¬ 𝐴 ∈ (𝐶 ∖ 𝐵))

Syntax hints:  ¬ wn 3   → wi 4   ∈ wcel 2109   ∖ cdif 3908

This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-3 8  ax-gen 1795  ax-4 1809  ax-5 1910  ax-6 1967  ax-7 2008  ax-8 2111  ax-9 2119  ax-ext 2701

This theorem depends on definitions:  df-bi 207  df-an 396  df-tru 1543  df-ex 1780  df-sb 2066  df-clab 2708  df-cleq 2721  df-clel 2803  df-v 3446  df-dif 3914

This theorem is referenced by:  peano5  7849  extmptsuppeq  8144  undifixp  8884  ssfin4  10239  isf32lem3  10284  isf34lem4  10306  xrinfmss  13246  restntr  23045  cmpcld  23265  reconnlem2  24692  lebnumlem1  24836  i1fd  25558  ssdifidlprm  33402  hgt750lemd  34612  fmlasucdisj  35359  dfon2lem6  35749  onsucconni  36398  meaiininclem  46457  caragendifcl  46485