Description: Idempotent law for the predecessor class. (Contributed by Scott Fenton, 29-Mar-2011)
Ref | Expression | ||
---|---|---|---|
Assertion | predidm | |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | df-pred | |
|
2 | df-pred | |
|
3 | inidm | |
|
4 | 3 | ineq2i | |
5 | 2 4 | eqtr4i | |
6 | inass | |
|
7 | 5 6 | eqtr4i | |
8 | 2 | ineq1i | |
9 | 7 8 | eqtr4i | |
10 | 1 9 | eqtr4i | |