Description: Inference adding a biconditional to the right in an equivalence. (Contributed by NM, 26-May-1993)
Ref | Expression | ||
---|---|---|---|
Hypothesis | bibi2i.1 | |
|
Assertion | bibi1i | |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | bibi2i.1 | |
|
2 | bicom | |
|
3 | 1 | bibi2i | |
4 | bicom | |
|
5 | 2 3 4 | 3bitri | |