Description: 2 divides 4. That means 4 is even. (Contributed by AV, 23-Jul-2020) (Revised by AV, 4-Jul-2021)
| Ref | Expression | ||
|---|---|---|---|
| Assertion | z4even | |- 2 || 4 |
| Step | Hyp | Ref | Expression |
|---|---|---|---|
| 1 | 2z | |- 2 e. ZZ |
|
| 2 | dvdsmul1 | |- ( ( 2 e. ZZ /\ 2 e. ZZ ) -> 2 || ( 2 x. 2 ) ) |
|
| 3 | 1 1 2 | mp2an | |- 2 || ( 2 x. 2 ) |
| 4 | 2t2e4 | |- ( 2 x. 2 ) = 4 |
|
| 5 | 3 4 | breqtri | |- 2 || 4 |