Theorem elndif 4087

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 4086	. 2 ⊢ (𝐴 ∈ (𝐶 ∖ 𝐵) → ¬ 𝐴 ∈ 𝐵)
2	1	con2i 139	1 ⊢ (𝐴 ∈ 𝐵 → ¬ 𝐴 ∈ (𝐶 ∖ 𝐵))

Syntax hints:  ¬ wn 3   → wi 4   ∈ wcel 2114   ∖ cdif 3900

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 1912  ax-6 1969  ax-7 2010  ax-8 2116  ax-9 2124  ax-ext 2709

This theorem depends on definitions:  df-bi 207  df-an 396  df-tru 1545  df-ex 1782  df-sb 2069  df-clab 2716  df-cleq 2729  df-clel 2812  df-v 3444  df-dif 3906

This theorem is referenced by:  peano5  7845  extmptsuppeq  8140  undifixp  8884  ssfin4  10232  isf32lem3  10277  isf34lem4  10299  xrinfmss  13237  restntr  23138  cmpcld  23358  reconnlem2  24784  lebnumlem1  24928  i1fd  25650  ssdifidlprm  33551  hgt750lemd  34826  fmlasucdisj  35615  dfon2lem6  36002  onsucconni  36653  meaiininclem  46844  caragendifcl  46872