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Description: Multiply in the last term in a finite product. (Contributed by Scott Fenton, 27-Dec-2017)
| Ref | Expression | ||
|---|---|---|---|
| Hypotheses | fprodp1s.1 | |- ( ph -> N e. ( ZZ>= ` M ) ) |
|
| fprodp1s.2 | |- ( ( ph /\ k e. ( M ... ( N + 1 ) ) ) -> A e. CC ) |
||
| Assertion | fprodp1s | |- ( ph -> prod_ k e. ( M ... ( N + 1 ) ) A = ( prod_ k e. ( M ... N ) A x. [_ ( N + 1 ) / k ]_ A ) ) |
| Step | Hyp | Ref | Expression |
|---|---|---|---|
| 1 | fprodp1s.1 | |- ( ph -> N e. ( ZZ>= ` M ) ) |
|
| 2 | fprodp1s.2 | |- ( ( ph /\ k e. ( M ... ( N + 1 ) ) ) -> A e. CC ) |
|
| 3 | 2 | ralrimiva | |- ( ph -> A. k e. ( M ... ( N + 1 ) ) A e. CC ) |
| 4 | nfcsb1v | |- F/_ k [_ m / k ]_ A |
|
| 5 | 4 | nfel1 | |- F/ k [_ m / k ]_ A e. CC |
| 6 | csbeq1a | |- ( k = m -> A = [_ m / k ]_ A ) |
|
| 7 | 6 | eleq1d | |- ( k = m -> ( A e. CC <-> [_ m / k ]_ A e. CC ) ) |
| 8 | 5 7 | rspc | |- ( m e. ( M ... ( N + 1 ) ) -> ( A. k e. ( M ... ( N + 1 ) ) A e. CC -> [_ m / k ]_ A e. CC ) ) |
| 9 | 3 8 | mpan9 | |- ( ( ph /\ m e. ( M ... ( N + 1 ) ) ) -> [_ m / k ]_ A e. CC ) |
| 10 | csbeq1 | |- ( m = ( N + 1 ) -> [_ m / k ]_ A = [_ ( N + 1 ) / k ]_ A ) |
|
| 11 | 1 9 10 | fprodp1 | |- ( ph -> prod_ m e. ( M ... ( N + 1 ) ) [_ m / k ]_ A = ( prod_ m e. ( M ... N ) [_ m / k ]_ A x. [_ ( N + 1 ) / k ]_ A ) ) |
| 12 | nfcv | |- F/_ m A |
|
| 13 | 12 4 6 | cbvprodi | |- prod_ k e. ( M ... ( N + 1 ) ) A = prod_ m e. ( M ... ( N + 1 ) ) [_ m / k ]_ A |
| 14 | 12 4 6 | cbvprodi | |- prod_ k e. ( M ... N ) A = prod_ m e. ( M ... N ) [_ m / k ]_ A |
| 15 | 14 | oveq1i | |- ( prod_ k e. ( M ... N ) A x. [_ ( N + 1 ) / k ]_ A ) = ( prod_ m e. ( M ... N ) [_ m / k ]_ A x. [_ ( N + 1 ) / k ]_ A ) |
| 16 | 11 13 15 | 3eqtr4g | |- ( ph -> prod_ k e. ( M ... ( N + 1 ) ) A = ( prod_ k e. ( M ... N ) A x. [_ ( N + 1 ) / k ]_ A ) ) |