Description: Proof of bj-rabtr found automatically by the Metamath program "MM-PA> IMPROVE ALL / DEPTH 3 / 3" command followed by "MM-PA> MINIMIZE__WITH *". (Contributed by BJ, 22-Apr-2019) (Proof modification is discouraged.) (New usage is discouraged.)
| Ref | Expression | ||
|---|---|---|---|
| Assertion | bj-rabtrAUTO | |- { x e. A | T. } = A | 
| Step | Hyp | Ref | Expression | 
|---|---|---|---|
| 1 | ssrab2 |  |-  { x e. A | T. } C_ A | |
| 2 | ssid | |- A C_ A | |
| 3 | 2 | a1i | |- ( T. -> A C_ A ) | 
| 4 | simpl | |- ( ( T. /\ x e. A ) -> T. ) | |
| 5 | 3 4 | ssrabdv |  |-  ( T. -> A C_ { x e. A | T. } ) | 
| 6 | 5 | mptru |  |-  A C_ { x e. A | T. } | 
| 7 | 1 6 | eqssi |  |-  { x e. A | T. } = A |