Description: Membership in a power set, biconditional. (Contributed by Steven Nguyen, 17-Jul-2022) (Proof shortened by Steven Nguyen, 16-Sep-2022)
| Ref | Expression | ||
|---|---|---|---|
| Hypothesis | elpwbi.1 | ||
| Assertion | elpwbi |
| Step | Hyp | Ref | Expression |
|---|---|---|---|
| 1 | elpwbi.1 | ||
| 2 | 1 | elpw2 | |
| 3 | 2 | bicomi |