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Theorem npss0 4369
 Description: No set is a proper subset of the empty set. (Contributed by NM, 17-Jun-1998.) (Proof shortened by Andrew Salmon, 26-Jun-2011.) (Proof shortened by JJ, 14-Jul-2021.)
Assertion
Ref Expression
npss0 ¬ 𝐴 ⊊ ∅

Proof of Theorem npss0
StepHypRef Expression
1 0ss 4322 . 2 ∅ ⊆ 𝐴
2 ssnpss 4055 . 2 (∅ ⊆ 𝐴 → ¬ 𝐴 ⊊ ∅)
31, 2ax-mp 5 1 ¬ 𝐴 ⊊ ∅
 Colors of variables: wff setvar class Syntax hints:  ¬ wn 3   ⊆ wss 3908   ⊊ wpss 3909  ∅c0 4265 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 1911  ax-6 1970  ax-7 2015  ax-8 2116  ax-9 2124  ax-ext 2794 This theorem depends on definitions:  df-bi 210  df-an 400  df-ex 1782  df-sb 2070  df-clab 2801  df-cleq 2815  df-clel 2894  df-ne 3012  df-v 3471  df-dif 3911  df-in 3915  df-ss 3925  df-pss 3927  df-nul 4266 This theorem is referenced by:  pssnn  8724  pssn0  39358
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