Description: 8 is a positive integer. (Contributed by Mario Carneiro, 15-Sep-2013)
Ref | Expression | ||
---|---|---|---|
Assertion | 8nn | |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | df-8 | |
|
2 | 7nn | |
|
3 | peano2nn | |
|
4 | 2 3 | ax-mp | |
5 | 1 4 | eqeltri | |