Description: A number which is twice an integer is even. (Contributed by AV, 16-Jul-2021)
Ref | Expression | ||
---|---|---|---|
Assertion | 2teven | |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | 2z | |
|
2 | dvdsmul1 | |
|
3 | 1 2 | mpan | |
4 | 3 | adantr | |
5 | breq2 | |
|
6 | 5 | adantl | |
7 | 4 6 | mpbird | |