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Mirrors > Home > MPE Home > Th. List > ssn0 | Structured version Visualization version GIF version |
Description: A class with a nonempty subclass is nonempty. (Contributed by NM, 17-Feb-2007.) |
Ref | Expression |
---|---|
ssn0 | ⊢ ((𝐴 ⊆ 𝐵 ∧ 𝐴 ≠ ∅) → 𝐵 ≠ ∅) |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | sseq0 4409 | . . . 4 ⊢ ((𝐴 ⊆ 𝐵 ∧ 𝐵 = ∅) → 𝐴 = ∅) | |
2 | 1 | ex 412 | . . 3 ⊢ (𝐴 ⊆ 𝐵 → (𝐵 = ∅ → 𝐴 = ∅)) |
3 | 2 | necon3d 2959 | . 2 ⊢ (𝐴 ⊆ 𝐵 → (𝐴 ≠ ∅ → 𝐵 ≠ ∅)) |
4 | 3 | imp 406 | 1 ⊢ ((𝐴 ⊆ 𝐵 ∧ 𝐴 ≠ ∅) → 𝐵 ≠ ∅) |
Colors of variables: wff setvar class |
Syntax hints: → wi 4 ∧ wa 395 = wceq 1537 ≠ wne 2938 ⊆ wss 3963 ∅c0 4339 |
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 1908 ax-6 1965 ax-7 2005 ax-8 2108 ax-9 2116 ax-ext 2706 |
This theorem depends on definitions: df-bi 207 df-an 396 df-tru 1540 df-fal 1550 df-ex 1777 df-sb 2063 df-clab 2713 df-cleq 2727 df-clel 2814 df-ne 2939 df-dif 3966 df-ss 3980 df-nul 4340 |
This theorem is referenced by: unixp0 6305 frxp 8150 onfununi 8380 frmin 9787 carddomi2 10008 fin23lem21 10377 wunex2 10776 vdwmc2 17013 gsumval2 18712 subgint 19181 subrngint 20577 subrgint 20612 nzerooringczr 21509 hausnei2 23377 fbun 23864 fbfinnfr 23865 filuni 23909 isufil2 23932 ufileu 23943 filufint 23944 fmfnfm 23982 hausflim 24005 flimclslem 24008 fclsneii 24041 fclsbas 24045 fclsrest 24048 fclscf 24049 fclsfnflim 24051 flimfnfcls 24052 fclscmp 24054 ufilcmp 24056 isfcf 24058 fcfnei 24059 clssubg 24133 ustfilxp 24237 metustfbas 24586 restmetu 24599 reperflem 24854 metdseq0 24890 relcmpcmet 25366 bcthlem5 25376 minveclem4a 25478 dvlip 26047 wlkvtxiedg 29658 imadifxp 32621 bnj970 34940 neibastop1 36342 neibastop2 36344 heibor1lem 37796 isnumbasabl 43095 dfacbasgrp 43097 ioossioobi 45470 islptre 45575 stoweidlem35 45991 stoweidlem39 45995 fourierdlem46 46108 |
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