Description: A set is an element of its power set. (Contributed by Stefan O'Rear, 1-Feb-2015) (Proof shortened by Umit Teoman Dogan, 10-Jun-2026)
| Ref | Expression | ||
|---|---|---|---|
| Assertion | pwidg | |- ( A e. V -> A e. ~P A ) |
| Step | Hyp | Ref | Expression |
|---|---|---|---|
| 1 | elex | |- ( A e. V -> A e. _V ) |
|
| 2 | ssidd | |- ( A e. V -> A C_ A ) |
|
| 3 | 1 2 | elpwd | |- ( A e. V -> A e. ~P A ) |