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| Description: One is a natural number. |
| Ref | Expression |
|---|---|
| 1onn |
|
| Step | Hyp | Ref | Expression |
|---|---|---|---|
| 1 | df-1o 4269 |
. 2
| |
| 2 | peano1 3237 |
. . 3
| |
| 3 | peano2 3238 |
. . 3
| |
| 4 | 2, 3 | ax-mp 7 |
. 2
|
| 5 | 1, 4 | eqeltri 1587 |
1
|
| Colors of variables: wff set class |
| Syntax hints: |
| This theorem is referenced by: 2onn 4394 nneob 4395 snfi 4573 pwfi 4714 oancom 4779 card1 4981 unxpdomlem 4993 unxpdom2 4995 nnacda 5090 1pi 5165 1lt2pi 5186 indpi 5188 infxpidmlem1 7764 infxpidmlem12 7775 infpss 7786 infmap2 7793 setwoe 10828 top2usne 11051 |
| This theorem was proved from axioms: ax-1 4 ax-2 5 ax-3 6 ax-mp 7 ax-7 998 ax-gen 999 ax-8 1000 ax-10 1002 ax-11 1003 ax-12 1004 ax-13 1005 ax-14 1006 ax-17 1007 ax-4 1009 ax-5o 1011 ax-6o 1014 ax-9o 1159 ax-10o 1177 ax-16 1247 ax-11o 1255 ax-ext 1500 ax-sep 2777 ax-nul 2784 ax-pow 2818 ax-pr 2855 ax-un 3089 |
| This theorem depends on definitions: df-bi 145 df-or 222 df-an 223 df-3or 782 df-3an 783 df-ex 1017 df-sb 1209 df-eu 1421 df-mo 1422 df-clab 1506 df-cleq 1511 df-clel 1514 df-ne 1630 df-ral 1695 df-rex 1696 df-v 1858 df-dif 2101 df-un 2102 df-in 2103 df-ss 2105 df-nul 2333 df-if 2416 df-pw 2459 df-sn 2470 df-pr 2471 df-tp 2473 df-op 2474 df-uni 2570 df-br 2693 df-opab 2741 df-tr 2755 df-eprel 2910 df-po 2918 df-so 2929 df-fr 2947 df-we 2962 df-ord 2978 df-on 2979 df-lim 2980 df-suc 2981 df-om 3219 df-1o 4269 |