Description: Synonym for logical equivalence. (Contributed by RP, 24-Dec-2019) (Proof modification is discouraged.)
Ref | Expression | ||
---|---|---|---|
Assertion | frege54cor0a |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | ax-frege28 | ||
2 | 1 | anim2i | |
3 | con4 | ||
4 | 3 | anim2i | |
5 | 2 4 | impbii | |
6 | dfbi2 | ||
7 | dfifp2 | ||
8 | 5 6 7 | 3bitr4i |