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Theorem eldifbd 2930
Description: If a class is in the difference of two classes, it is not in the subtrahend. One-way deduction form of eldif 2927. (Contributed by David Moews, 1-May-2017.)
Hypothesis
Ref Expression
eldifbd.1 (𝜑𝐴 ∈ (𝐵𝐶))
Assertion
Ref Expression
eldifbd (𝜑 → ¬ 𝐴𝐶)

Proof of Theorem eldifbd
StepHypRef Expression
1 eldifbd.1 . . 3 (𝜑𝐴 ∈ (𝐵𝐶))
2 eldif 2927 . . 3 (𝐴 ∈ (𝐵𝐶) ↔ (𝐴𝐵 ∧ ¬ 𝐴𝐶))
31, 2sylib 127 . 2 (𝜑 → (𝐴𝐵 ∧ ¬ 𝐴𝐶))
43simprd 107 1 (𝜑 → ¬ 𝐴𝐶)
Colors of variables: wff set class
Syntax hints:  ¬ wn 3  wi 4  wa 97  wcel 1393  cdif 2914
This theorem was proved from axioms:  ax-1 5  ax-2 6  ax-mp 7  ax-ia1 99  ax-ia2 100  ax-ia3 101  ax-in1 544  ax-in2 545  ax-io 630  ax-5 1336  ax-7 1337  ax-gen 1338  ax-ie1 1382  ax-ie2 1383  ax-8 1395  ax-10 1396  ax-11 1397  ax-i12 1398  ax-bndl 1399  ax-4 1400  ax-17 1419  ax-i9 1423  ax-ial 1427  ax-i5r 1428  ax-ext 2022
This theorem depends on definitions:  df-bi 110  df-tru 1246  df-nf 1350  df-sb 1646  df-clab 2027  df-cleq 2033  df-clel 2036  df-nfc 2167  df-v 2559  df-dif 2920
This theorem is referenced by:  fidifsnen  6331  fiunsnnn  6338
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