Description: Equality theorem for the predecessor class. (Contributed by Scott Fenton, 2-Feb-2011)
Ref | Expression | ||
---|---|---|---|
Assertion | predeq2 | |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | eqid | |
|
2 | eqid | |
|
3 | predeq123 | |
|
4 | 1 2 3 | mp3an13 | |