Description: Characterization of the elements of B in terms of elements of its tagged version. (Contributed by BJ, 6-Oct-2018)
| Ref | Expression | ||
|---|---|---|---|
| Assertion | bj-tagcg | |- ( A e. V -> ( A e. B <-> { A } e. tag B ) ) | 
| Step | Hyp | Ref | Expression | 
|---|---|---|---|
| 1 | bj-snglc |  |-  ( A e. B <-> { A } e. sngl B ) | |
| 2 | bj-sngltag |  |-  ( A e. V -> ( { A } e. sngl B <-> { A } e. tag B ) ) | |
| 3 | 1 2 | bitrid |  |-  ( A e. V -> ( A e. B <-> { A } e. tag B ) ) |