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Description: Generalization of the Axiom of Choice to classes. Slightly strengthened version of ac6s3 . (Contributed by NM, 29-Sep-2006)
| Ref | Expression | ||
|---|---|---|---|
| Hypotheses | ac6s.1 | |- A e. _V |
|
| ac6s.2 | |- ( y = ( f ` x ) -> ( ph <-> ps ) ) |
||
| Assertion | ac6s2 | |- ( A. x e. A E. y ph -> E. f ( f Fn A /\ A. x e. A ps ) ) |
| Step | Hyp | Ref | Expression |
|---|---|---|---|
| 1 | ac6s.1 | |- A e. _V |
|
| 2 | ac6s.2 | |- ( y = ( f ` x ) -> ( ph <-> ps ) ) |
|
| 3 | rexv | |- ( E. y e. _V ph <-> E. y ph ) |
|
| 4 | 3 | ralbii | |- ( A. x e. A E. y e. _V ph <-> A. x e. A E. y ph ) |
| 5 | 1 2 | ac6s | |- ( A. x e. A E. y e. _V ph -> E. f ( f : A --> _V /\ A. x e. A ps ) ) |
| 6 | ffn | |- ( f : A --> _V -> f Fn A ) |
|
| 7 | 6 | anim1i | |- ( ( f : A --> _V /\ A. x e. A ps ) -> ( f Fn A /\ A. x e. A ps ) ) |
| 8 | 7 | eximi | |- ( E. f ( f : A --> _V /\ A. x e. A ps ) -> E. f ( f Fn A /\ A. x e. A ps ) ) |
| 9 | 5 8 | syl | |- ( A. x e. A E. y e. _V ph -> E. f ( f Fn A /\ A. x e. A ps ) ) |
| 10 | 4 9 | sylbir | |- ( A. x e. A E. y ph -> E. f ( f Fn A /\ A. x e. A ps ) ) |