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Description: The absolute value of the product of the elements of a finite subset of the integers is divisible by each element of this subset. (Contributed by AV, 21-Aug-2020)
| Ref | Expression | ||
|---|---|---|---|
| Hypotheses | absproddvds.s | |- ( ph -> Z C_ ZZ ) |
|
| absproddvds.f | |- ( ph -> Z e. Fin ) |
||
| absproddvds.p | |- P = ( abs ` prod_ z e. Z z ) |
||
| Assertion | absproddvds | |- ( ph -> A. m e. Z m || P ) |
| Step | Hyp | Ref | Expression |
|---|---|---|---|
| 1 | absproddvds.s | |- ( ph -> Z C_ ZZ ) |
|
| 2 | absproddvds.f | |- ( ph -> Z e. Fin ) |
|
| 3 | absproddvds.p | |- P = ( abs ` prod_ z e. Z z ) |
|
| 4 | 2 1 | fproddvdsd | |- ( ph -> A. m e. Z m || prod_ z e. Z z ) |
| 5 | 1 | sselda | |- ( ( ph /\ m e. Z ) -> m e. ZZ ) |
| 6 | 1 | sselda | |- ( ( ph /\ z e. Z ) -> z e. ZZ ) |
| 7 | 2 6 | fprodzcl | |- ( ph -> prod_ z e. Z z e. ZZ ) |
| 8 | 7 | adantr | |- ( ( ph /\ m e. Z ) -> prod_ z e. Z z e. ZZ ) |
| 9 | dvdsabsb | |- ( ( m e. ZZ /\ prod_ z e. Z z e. ZZ ) -> ( m || prod_ z e. Z z <-> m || ( abs ` prod_ z e. Z z ) ) ) |
|
| 10 | 5 8 9 | syl2anc | |- ( ( ph /\ m e. Z ) -> ( m || prod_ z e. Z z <-> m || ( abs ` prod_ z e. Z z ) ) ) |
| 11 | 10 | biimpd | |- ( ( ph /\ m e. Z ) -> ( m || prod_ z e. Z z -> m || ( abs ` prod_ z e. Z z ) ) ) |
| 12 | 11 | ralimdva | |- ( ph -> ( A. m e. Z m || prod_ z e. Z z -> A. m e. Z m || ( abs ` prod_ z e. Z z ) ) ) |
| 13 | 4 12 | mpd | |- ( ph -> A. m e. Z m || ( abs ` prod_ z e. Z z ) ) |
| 14 | 3 | breq2i | |- ( m || P <-> m || ( abs ` prod_ z e. Z z ) ) |
| 15 | 14 | ralbii | |- ( A. m e. Z m || P <-> A. m e. Z m || ( abs ` prod_ z e. Z z ) ) |
| 16 | 13 15 | sylibr | |- ( ph -> A. m e. Z m || P ) |