Description: 2 does not divide 3. That means 3 is odd. (Contributed by AV, 28-Feb-2021) (Proof shortened by Steven Nguyen, 3-May-2023)
| Ref | Expression | ||
|---|---|---|---|
| Assertion | n2dvds3 | |- -. 2 || 3 | 
| Step | Hyp | Ref | Expression | 
|---|---|---|---|
| 1 | 3halfnz | |- -. ( 3 / 2 ) e. ZZ | |
| 2 | 3z | |- 3 e. ZZ | |
| 3 | evend2 | |- ( 3 e. ZZ -> ( 2 || 3 <-> ( 3 / 2 ) e. ZZ ) ) | |
| 4 | 2 3 | ax-mp | |- ( 2 || 3 <-> ( 3 / 2 ) e. ZZ ) | 
| 5 | 1 4 | mtbir | |- -. 2 || 3 |