Description: The nonnegative integers form an ordered monoid. (Contributed by Thierry Arnoux, 23-Mar-2018)
Ref | Expression | ||
---|---|---|---|
Assertion | nn0omnd | |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | df-refld | |
|
2 | 1 | oveq1i | |
3 | reex | |
|
4 | nn0ssre | |
|
5 | ressabs | |
|
6 | 3 4 5 | mp2an | |
7 | 2 6 | eqtri | |
8 | reofld | |
|
9 | isofld | |
|
10 | 9 | simprbi | |
11 | orngogrp | |
|
12 | isogrp | |
|
13 | 12 | simprbi | |
14 | 10 11 13 | 3syl | |
15 | 8 14 | ax-mp | |
16 | nn0subm | |
|
17 | eqid | |
|
18 | 17 | submmnd | |
19 | 16 18 | ax-mp | |
20 | 7 19 | eqeltri | |
21 | submomnd | |
|
22 | 15 20 21 | mp2an | |
23 | 7 22 | eqeltrri | |