Theorem elndif 4099

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 4098	. 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 3914

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 2702

This theorem depends on definitions:  df-bi 207  df-an 396  df-tru 1543  df-ex 1780  df-sb 2066  df-clab 2709  df-cleq 2722  df-clel 2804  df-v 3452  df-dif 3920

This theorem is referenced by:  peano5  7872  extmptsuppeq  8170  undifixp  8910  ssfin4  10270  isf32lem3  10315  isf34lem4  10337  xrinfmss  13277  restntr  23076  cmpcld  23296  reconnlem2  24723  lebnumlem1  24867  i1fd  25589  ssdifidlprm  33436  hgt750lemd  34646  fmlasucdisj  35393  dfon2lem6  35783  onsucconni  36432  meaiininclem  46491  caragendifcl  46519