Description: 2 is not an odd number. (Contributed by AV, 3-Feb-2020) (Revised by AV, 18-Jun-2020)
| Ref | Expression | ||
|---|---|---|---|
| Assertion | 2noddALTV | |- 2 e/ Odd | 
| Step | Hyp | Ref | Expression | 
|---|---|---|---|
| 1 | 2evenALTV | |- 2 e. Even | |
| 2 | df-nel | |- ( 2 e/ Odd <-> -. 2 e. Odd ) | |
| 3 | 2z | |- 2 e. ZZ | |
| 4 | zeo2ALTV | |- ( 2 e. ZZ -> ( 2 e. Even <-> -. 2 e. Odd ) ) | |
| 5 | 4 | bicomd | |- ( 2 e. ZZ -> ( -. 2 e. Odd <-> 2 e. Even ) ) | 
| 6 | 3 5 | ax-mp | |- ( -. 2 e. Odd <-> 2 e. Even ) | 
| 7 | 2 6 | bitri | |- ( 2 e/ Odd <-> 2 e. Even ) | 
| 8 | 1 7 | mpbir | |- 2 e/ Odd |