Description: The value of the predecessor class over the naturals. (Contributed by Scott Fenton, 6-Aug-2013)
Ref | Expression | ||
---|---|---|---|
Assertion | prednn |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | nnuz | ||
2 | predeq2 | ||
3 | 1 2 | ax-mp | |
4 | elnnuz | ||
5 | preduz | ||
6 | 4 5 | sylbi | |
7 | 3 6 | eqtrid |