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Theorem ss0b 3299
 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 3298 . . 3 ∅ ⊆ 𝐴
2 eqss 3023 . . 3 (𝐴 = ∅ ↔ (𝐴 ⊆ ∅ ∧ ∅ ⊆ 𝐴))
31, 2mpbiran2 883 . 2 (𝐴 = ∅ ↔ 𝐴 ⊆ ∅)
43bicomi 130 1 (𝐴 ⊆ ∅ ↔ 𝐴 = ∅)
 Colors of variables: wff set class Syntax hints:   ↔ wb 103   = wceq 1285   ⊆ wss 2982  ∅c0 3267 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 1377  ax-7 1378  ax-gen 1379  ax-ie1 1423  ax-ie2 1424  ax-8 1436  ax-10 1437  ax-11 1438  ax-i12 1439  ax-bndl 1440  ax-4 1441  ax-17 1460  ax-i9 1464  ax-ial 1468  ax-i5r 1469  ax-ext 2065 This theorem depends on definitions:  df-bi 115  df-tru 1288  df-nf 1391  df-sb 1688  df-clab 2070  df-cleq 2076  df-clel 2079  df-nfc 2212  df-v 2612  df-dif 2984  df-in 2988  df-ss 2995  df-nul 3268 This theorem is referenced by:  ss0  3300  un00  3306  ssdisj  3316  pw0  3552  card0  6568
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