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Mirrors > Home > MPE Home > Th. List > 0pss | Structured version Visualization version GIF version |
Description: The null set is a proper subset of any nonempty set. (Contributed by NM, 27-Feb-1996.) |
Ref | Expression |
---|---|
0pss | ⊢ (∅ ⊊ 𝐴 ↔ 𝐴 ≠ ∅) |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | 0ss 4349 | . . 3 ⊢ ∅ ⊆ 𝐴 | |
2 | df-pss 3953 | . . 3 ⊢ (∅ ⊊ 𝐴 ↔ (∅ ⊆ 𝐴 ∧ ∅ ≠ 𝐴)) | |
3 | 1, 2 | mpbiran 707 | . 2 ⊢ (∅ ⊊ 𝐴 ↔ ∅ ≠ 𝐴) |
4 | necom 3069 | . 2 ⊢ (∅ ≠ 𝐴 ↔ 𝐴 ≠ ∅) | |
5 | 3, 4 | bitri 277 | 1 ⊢ (∅ ⊊ 𝐴 ↔ 𝐴 ≠ ∅) |
Colors of variables: wff setvar class |
Syntax hints: ↔ wb 208 ≠ wne 3016 ⊆ wss 3935 ⊊ wpss 3936 ∅c0 4290 |
This theorem was proved from axioms: ax-mp 5 ax-1 6 ax-2 7 ax-3 8 ax-gen 1792 ax-4 1806 ax-5 1907 ax-6 1966 ax-7 2011 ax-8 2112 ax-9 2120 ax-10 2141 ax-11 2157 ax-12 2173 ax-ext 2793 |
This theorem depends on definitions: df-bi 209 df-an 399 df-or 844 df-tru 1536 df-ex 1777 df-nf 1781 df-sb 2066 df-clab 2800 df-cleq 2814 df-clel 2893 df-ne 3017 df-dif 3938 df-in 3942 df-ss 3951 df-pss 3953 df-nul 4291 |
This theorem is referenced by: php 8695 zornn0g 9921 prn0 10405 genpn0 10419 nqpr 10430 ltexprlem5 10456 reclem2pr 10464 suplem1pr 10468 alexsubALTlem4 22652 bj-2upln0 34330 bj-2upln1upl 34331 0pssin 40109 |
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