Description: 9 is an odd Goldbach number. (Contributed by AV, 26-Jul-2020)
Ref | Expression | ||
---|---|---|---|
Assertion | 9gbo | |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | df-9 | |
|
2 | 8even | |
|
3 | evenp1odd | |
|
4 | 2 3 | ax-mp | |
5 | 1 4 | eqeltri | |
6 | 3prm | |
|
7 | 3odd | |
|
8 | 7 7 7 | 3pm3.2i | |
9 | gbpart9 | |
|
10 | 8 9 | pm3.2i | |
11 | eleq1 | |
|
12 | 11 | 3anbi3d | |
13 | oveq2 | |
|
14 | 13 | eqeq2d | |
15 | 12 14 | anbi12d | |
16 | 15 | rspcev | |
17 | 6 10 16 | mp2an | |
18 | eleq1 | |
|
19 | 18 | 3anbi1d | |
20 | oveq1 | |
|
21 | 20 | oveq1d | |
22 | 21 | eqeq2d | |
23 | 19 22 | anbi12d | |
24 | 23 | rexbidv | |
25 | eleq1 | |
|
26 | 25 | 3anbi2d | |
27 | oveq2 | |
|
28 | 27 | oveq1d | |
29 | 28 | eqeq2d | |
30 | 26 29 | anbi12d | |
31 | 30 | rexbidv | |
32 | 24 31 | rspc2ev | |
33 | 6 6 17 32 | mp3an | |
34 | isgbo | |
|
35 | 5 33 34 | mpbir2an | |