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Theorem ss0b 3310
Description: Any subset of the empty set is empty. Theorem 5 of [Suppes] p. 23 and its converse. (Contributed by NM, 17-Sep-2003.)
Assertion
Ref Expression
ss0b (𝐴 ⊆ ∅ ↔ 𝐴 = ∅)

Proof of Theorem ss0b
StepHypRef Expression
1 0ss 3309 . . 3 ∅ ⊆ 𝐴
2 eqss 3029 . . 3 (𝐴 = ∅ ↔ (𝐴 ⊆ ∅ ∧ ∅ ⊆ 𝐴))
31, 2mpbiran2 885 . 2 (𝐴 = ∅ ↔ 𝐴 ⊆ ∅)
43bicomi 130 1 (𝐴 ⊆ ∅ ↔ 𝐴 = ∅)
Colors of variables: wff set class
Syntax hints:  wb 103   = wceq 1287  wss 2988  c0 3275
This theorem was proved from axioms:  ax-1 5  ax-2 6  ax-mp 7  ax-ia1 104  ax-ia2 105  ax-ia3 106  ax-in1 577  ax-in2 578  ax-io 663  ax-5 1379  ax-7 1380  ax-gen 1381  ax-ie1 1425  ax-ie2 1426  ax-8 1438  ax-10 1439  ax-11 1440  ax-i12 1441  ax-bndl 1442  ax-4 1443  ax-17 1462  ax-i9 1466  ax-ial 1470  ax-i5r 1471  ax-ext 2067
This theorem depends on definitions:  df-bi 115  df-tru 1290  df-nf 1393  df-sb 1690  df-clab 2072  df-cleq 2078  df-clel 2081  df-nfc 2214  df-v 2617  df-dif 2990  df-in 2994  df-ss 3001  df-nul 3276
This theorem is referenced by:  ss0  3311  un00  3317  ssdisj  3327  pw0  3569  card0  6763
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