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Mirrors > Home > ILE Home > Th. List > 2nn | GIF version |
Description: 2 is a positive integer. (Contributed by NM, 20-Aug-2001.) |
Ref | Expression |
---|---|
2nn | ⊢ 2 ∈ ℕ |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | df-2 8779 | . 2 ⊢ 2 = (1 + 1) | |
2 | 1nn 8731 | . . 3 ⊢ 1 ∈ ℕ | |
3 | peano2nn 8732 | . . 3 ⊢ (1 ∈ ℕ → (1 + 1) ∈ ℕ) | |
4 | 2, 3 | ax-mp 5 | . 2 ⊢ (1 + 1) ∈ ℕ |
5 | 1, 4 | eqeltri 2212 | 1 ⊢ 2 ∈ ℕ |
Colors of variables: wff set class |
Syntax hints: ∈ wcel 1480 (class class class)co 5774 1c1 7621 + caddc 7623 ℕcn 8720 2c2 8771 |
This theorem was proved from axioms: ax-mp 5 ax-1 6 ax-2 7 ax-ia1 105 ax-ia2 106 ax-ia3 107 ax-io 698 ax-5 1423 ax-7 1424 ax-gen 1425 ax-ie1 1469 ax-ie2 1470 ax-8 1482 ax-10 1483 ax-11 1484 ax-i12 1485 ax-bndl 1486 ax-4 1487 ax-17 1506 ax-i9 1510 ax-ial 1514 ax-i5r 1515 ax-ext 2121 ax-sep 4046 ax-cnex 7711 ax-resscn 7712 ax-1re 7714 ax-addrcl 7717 |
This theorem depends on definitions: df-bi 116 df-3an 964 df-tru 1334 df-nf 1437 df-sb 1736 df-clab 2126 df-cleq 2132 df-clel 2135 df-nfc 2270 df-ral 2421 df-rex 2422 df-v 2688 df-un 3075 df-in 3077 df-ss 3084 df-sn 3533 df-pr 3534 df-op 3536 df-uni 3737 df-int 3772 df-br 3930 df-iota 5088 df-fv 5131 df-ov 5777 df-inn 8721 df-2 8779 |
This theorem is referenced by: 3nn 8882 2nn0 8994 2z 9082 uz3m2nn 9368 ige2m1fz1 9889 qbtwnre 10034 flhalf 10075 sqeq0 10356 sqeq0d 10423 facavg 10492 bcn2 10510 resqrexlemnm 10790 abs00ap 10834 geo2sum 11283 geo2lim 11285 ege2le3 11377 ef01bndlem 11463 mod2eq0even 11575 mod2eq1n2dvds 11576 sqgcd 11717 3lcm2e6woprm 11767 prm2orodd 11807 3prm 11809 4nprm 11810 divgcdodd 11821 isevengcd2 11836 3lcm2e6 11838 pw2dvdslemn 11843 pw2dvds 11844 pw2dvdseulemle 11845 oddpwdclemxy 11847 oddpwdclemodd 11850 oddpwdclemdc 11851 oddpwdc 11852 sqpweven 11853 2sqpwodd 11854 evenennn 11906 exmidunben 11939 plusgndx 12052 plusgid 12053 plusgslid 12054 grpstrg 12066 grpbaseg 12067 grpplusgg 12068 rngstrg 12074 lmodstrd 12092 topgrpstrd 12110 dsndx 12117 dsid 12118 dsslid 12119 dveflem 12855 ex-fl 12937 ex-ceil 12938 |
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