Description: Alternate definition for even numbers. (Contributed by AV, 18-Jun-2020)
Ref | Expression | ||
---|---|---|---|
Assertion | dfeven2 | |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | dfeven4 | |
|
2 | eqcom | |
|
3 | 2cnd | |
|
4 | zcn | |
|
5 | 4 | adantl | |
6 | 3 5 | mulcomd | |
7 | 6 | eqeq1d | |
8 | 2 7 | syl5bb | |
9 | 8 | rexbidva | |
10 | 2z | |
|
11 | divides | |
|
12 | 10 11 | mpan | |
13 | 9 12 | bitr4d | |
14 | 13 | rabbiia | |
15 | 1 14 | eqtri | |