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 ∈ ℤ | |
| 2 | dvdsmul1 | ⊢ ( ( 2 ∈ ℤ ∧ 2 ∈ ℤ ) → 2 ∥ ( 2 · 2 ) ) | |
| 3 | 1 1 2 | mp2an | ⊢ 2 ∥ ( 2 · 2 ) |
| 4 | 2t2e4 | ⊢ ( 2 · 2 ) = 4 | |
| 5 | 3 4 | breqtri | ⊢ 2 ∥ 4 |