Description: A composition is not affected by a double converse of its first argument. (Contributed by NM, 8-Oct-2007)
Ref | Expression | ||
---|---|---|---|
Assertion | cocnvcnv1 | |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | cnvcnv2 | |
|
2 | 1 | coeq1i | |
3 | ssv | |
|
4 | cores | |
|
5 | 3 4 | ax-mp | |
6 | 2 5 | eqtri | |