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| Mirrors > Home > NFE Home > Th. List > 0cex | Unicode version | ||
| Description: Cardinal zero is a set. (Contributed by SF, 14-Jan-2015.) | 
| Ref | Expression | 
|---|---|
| 0cex | 
 | 
| Step | Hyp | Ref | Expression | 
|---|---|---|---|
| 1 | df-0c 4378 | 
. 2
 | |
| 2 | snex 4112 | 
. 2
 | |
| 3 | 1, 2 | eqeltri 2423 | 
1
 | 
| Colors of variables: wff setvar class | 
| Syntax hints:     | 
| This theorem was proved from axioms: ax-mp 5 ax-1 6 ax-2 7 ax-3 8 ax-gen 1546 ax-5 1557 ax-17 1616 ax-9 1654 ax-8 1675 ax-6 1729 ax-7 1734 ax-11 1746 ax-12 1925 ax-ext 2334 ax-nin 4079 ax-sn 4088 | 
| This theorem depends on definitions: df-bi 177 df-or 359 df-an 360 df-nan 1288 df-tru 1319 df-ex 1542 df-nf 1545 df-sb 1649 df-clab 2340 df-cleq 2346 df-clel 2349 df-nfc 2479 df-ne 2519 df-v 2862 df-nin 3212 df-compl 3213 df-in 3214 df-un 3215 df-dif 3216 df-ss 3260 df-nul 3552 df-sn 3742 df-0c 4378 | 
| This theorem is referenced by: peano1 4403 findsd 4411 ltfintri 4467 0ceven 4506 0cnelphi 4598 proj1op 4601 proj2op 4602 dfnnc3 5886 ce0nn 6181 lec0cg 6199 frecxp 6315 dmfrec 6317 fnfreclem2 6319 fnfreclem3 6320 | 
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