Description: Generalization of the Axiom of Choice to classes. Theorem 10.46 of TakeutiZaring p. 97. (Contributed by NM, 3-Nov-2004)
Ref | Expression | ||
---|---|---|---|
Hypotheses | ac6s.1 | |- A e. _V |
|
ac6s.2 | |- ( y = ( f ` x ) -> ( ph <-> ps ) ) |
||
Assertion | ac6s3 | |- ( A. x e. A E. y ph -> E. f A. x e. A ps ) |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | ac6s.1 | |- A e. _V |
|
2 | ac6s.2 | |- ( y = ( f ` x ) -> ( ph <-> ps ) ) |
|
3 | 1 2 | ac6s2 | |- ( A. x e. A E. y ph -> E. f ( f Fn A /\ A. x e. A ps ) ) |
4 | exsimpr | |- ( E. f ( f Fn A /\ A. x e. A ps ) -> E. f A. x e. A ps ) |
|
5 | 3 4 | syl | |- ( A. x e. A E. y ph -> E. f A. x e. A ps ) |