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Description: Restricted uniqueness "picks" a member of a subclass. (Contributed by Mario Carneiro, 15-Dec-2013) (Proof shortened by Mario Carneiro, 19-Nov-2016)
| Ref | Expression | ||
|---|---|---|---|
| Assertion | reupick2 | |- ( ( ( A. x e. A ( ps -> ph ) /\ E. x e. A ps /\ E! x e. A ph ) /\ x e. A ) -> ( ph <-> ps ) ) |
| Step | Hyp | Ref | Expression |
|---|---|---|---|
| 1 | ancr | |- ( ( ps -> ph ) -> ( ps -> ( ph /\ ps ) ) ) |
|
| 2 | 1 | ralimi | |- ( A. x e. A ( ps -> ph ) -> A. x e. A ( ps -> ( ph /\ ps ) ) ) |
| 3 | rexim | |- ( A. x e. A ( ps -> ( ph /\ ps ) ) -> ( E. x e. A ps -> E. x e. A ( ph /\ ps ) ) ) |
|
| 4 | 2 3 | syl | |- ( A. x e. A ( ps -> ph ) -> ( E. x e. A ps -> E. x e. A ( ph /\ ps ) ) ) |
| 5 | reupick3 | |- ( ( E! x e. A ph /\ E. x e. A ( ph /\ ps ) /\ x e. A ) -> ( ph -> ps ) ) |
|
| 6 | 5 | 3exp | |- ( E! x e. A ph -> ( E. x e. A ( ph /\ ps ) -> ( x e. A -> ( ph -> ps ) ) ) ) |
| 7 | 6 | com12 | |- ( E. x e. A ( ph /\ ps ) -> ( E! x e. A ph -> ( x e. A -> ( ph -> ps ) ) ) ) |
| 8 | 4 7 | syl6 | |- ( A. x e. A ( ps -> ph ) -> ( E. x e. A ps -> ( E! x e. A ph -> ( x e. A -> ( ph -> ps ) ) ) ) ) |
| 9 | 8 | 3imp1 | |- ( ( ( A. x e. A ( ps -> ph ) /\ E. x e. A ps /\ E! x e. A ph ) /\ x e. A ) -> ( ph -> ps ) ) |
| 10 | rsp | |- ( A. x e. A ( ps -> ph ) -> ( x e. A -> ( ps -> ph ) ) ) |
|
| 11 | 10 | 3ad2ant1 | |- ( ( A. x e. A ( ps -> ph ) /\ E. x e. A ps /\ E! x e. A ph ) -> ( x e. A -> ( ps -> ph ) ) ) |
| 12 | 11 | imp | |- ( ( ( A. x e. A ( ps -> ph ) /\ E. x e. A ps /\ E! x e. A ph ) /\ x e. A ) -> ( ps -> ph ) ) |
| 13 | 9 12 | impbid | |- ( ( ( A. x e. A ( ps -> ph ) /\ E. x e. A ps /\ E! x e. A ph ) /\ x e. A ) -> ( ph <-> ps ) ) |