Metamath Proof Explorer


Theorem nn0omnd

Description: The nonnegative integers form an ordered monoid. (Contributed by Thierry Arnoux, 23-Mar-2018)

Ref Expression
Assertion nn0omnd
|- ( CCfld |`s NN0 ) e. oMnd

Proof

Step Hyp Ref Expression
1 df-refld
 |-  RRfld = ( CCfld |`s RR )
2 1 oveq1i
 |-  ( RRfld |`s NN0 ) = ( ( CCfld |`s RR ) |`s NN0 )
3 reex
 |-  RR e. _V
4 nn0ssre
 |-  NN0 C_ RR
5 ressabs
 |-  ( ( RR e. _V /\ NN0 C_ RR ) -> ( ( CCfld |`s RR ) |`s NN0 ) = ( CCfld |`s NN0 ) )
6 3 4 5 mp2an
 |-  ( ( CCfld |`s RR ) |`s NN0 ) = ( CCfld |`s NN0 )
7 2 6 eqtri
 |-  ( RRfld |`s NN0 ) = ( CCfld |`s NN0 )
8 reofld
 |-  RRfld e. oField
9 isofld
 |-  ( RRfld e. oField <-> ( RRfld e. Field /\ RRfld e. oRing ) )
10 9 simprbi
 |-  ( RRfld e. oField -> RRfld e. oRing )
11 orngogrp
 |-  ( RRfld e. oRing -> RRfld e. oGrp )
12 isogrp
 |-  ( RRfld e. oGrp <-> ( RRfld e. Grp /\ RRfld e. oMnd ) )
13 12 simprbi
 |-  ( RRfld e. oGrp -> RRfld e. oMnd )
14 10 11 13 3syl
 |-  ( RRfld e. oField -> RRfld e. oMnd )
15 8 14 ax-mp
 |-  RRfld e. oMnd
16 nn0subm
 |-  NN0 e. ( SubMnd ` CCfld )
17 eqid
 |-  ( CCfld |`s NN0 ) = ( CCfld |`s NN0 )
18 17 submmnd
 |-  ( NN0 e. ( SubMnd ` CCfld ) -> ( CCfld |`s NN0 ) e. Mnd )
19 16 18 ax-mp
 |-  ( CCfld |`s NN0 ) e. Mnd
20 7 19 eqeltri
 |-  ( RRfld |`s NN0 ) e. Mnd
21 submomnd
 |-  ( ( RRfld e. oMnd /\ ( RRfld |`s NN0 ) e. Mnd ) -> ( RRfld |`s NN0 ) e. oMnd )
22 15 20 21 mp2an
 |-  ( RRfld |`s NN0 ) e. oMnd
23 7 22 eqeltrri
 |-  ( CCfld |`s NN0 ) e. oMnd