Theorem eldifad 3082

Description: If a class is in the difference of two classes, it is also in the minuend. One-way deduction form of eldif 3080. (Contributed by David Moews, 1-May-2017.)

Hypothesis

Ref	Expression
eldifad.1	⊢ (𝜑 → 𝐴 ∈ (𝐵 ∖ 𝐶))

Assertion

Ref	Expression
eldifad	⊢ (𝜑 → 𝐴 ∈ 𝐵)

Proof of Theorem eldifad

Step	Hyp	Ref	Expression
1		eldifad.1	. . 3 ⊢ (𝜑 → 𝐴 ∈ (𝐵 ∖ 𝐶))
2		eldif 3080	. . 3 ⊢ (𝐴 ∈ (𝐵 ∖ 𝐶) ↔ (𝐴 ∈ 𝐵 ∧ ¬ 𝐴 ∈ 𝐶))
3	1, 2	sylib 121	. 2 ⊢ (𝜑 → (𝐴 ∈ 𝐵 ∧ ¬ 𝐴 ∈ 𝐶))
4	3	simpld 111	1 ⊢ (𝜑 → 𝐴 ∈ 𝐵)

Syntax hints:  ¬ wn 3   → wi 4   ∧ wa 103   ∈ wcel 1480   ∖ cdif 3068

This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-ia1 105  ax-ia2 106  ax-ia3 107  ax-in1 603  ax-in2 604  ax-io 698  ax-5 1423  ax-7 1424  ax-gen 1425  ax-ie1 1469  ax-ie2 1470  ax-8 1482  ax-10 1483  ax-11 1484  ax-i12 1485  ax-bndl 1486  ax-4 1487  ax-17 1506  ax-i9 1510  ax-ial 1514  ax-i5r 1515  ax-ext 2121

This theorem depends on definitions:  df-bi 116  df-tru 1334  df-nf 1437  df-sb 1736  df-clab 2126  df-cleq 2132  df-clel 2135  df-nfc 2270  df-v 2688  df-dif 3073

This theorem is referenced by:  fimax2gtri  6795  finexdc  6796  unfidisj  6810  undifdc  6812  ssfirab  6822  fnfi  6825  iunfidisj  6834  hashunlem  10550  zfz1isolemiso  10582  fsumrelem  11240  iuncld  12284  fsumcncntop  12725