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Description: The Chebyshev function is closed in the log-integers. (Contributed by Mario Carneiro, 22-Sep-2014) (Revised by Mario Carneiro, 7-Apr-2016)
| Ref | Expression | ||
|---|---|---|---|
| Assertion | efchtcl | |- ( A e. RR -> ( exp ` ( theta ` A ) ) e. NN ) |
| Step | Hyp | Ref | Expression |
|---|---|---|---|
| 1 | chtval | |- ( A e. RR -> ( theta ` A ) = sum_ p e. ( ( 0 [,] A ) i^i Prime ) ( log ` p ) ) |
|
| 2 | 1 | fveq2d | |- ( A e. RR -> ( exp ` ( theta ` A ) ) = ( exp ` sum_ p e. ( ( 0 [,] A ) i^i Prime ) ( log ` p ) ) ) |
| 3 | ppifi | |- ( A e. RR -> ( ( 0 [,] A ) i^i Prime ) e. Fin ) |
|
| 4 | simpr | |- ( ( A e. RR /\ p e. ( ( 0 [,] A ) i^i Prime ) ) -> p e. ( ( 0 [,] A ) i^i Prime ) ) |
|
| 5 | 4 | elin2d | |- ( ( A e. RR /\ p e. ( ( 0 [,] A ) i^i Prime ) ) -> p e. Prime ) |
| 6 | prmnn | |- ( p e. Prime -> p e. NN ) |
|
| 7 | 5 6 | syl | |- ( ( A e. RR /\ p e. ( ( 0 [,] A ) i^i Prime ) ) -> p e. NN ) |
| 8 | 7 | nnrpd | |- ( ( A e. RR /\ p e. ( ( 0 [,] A ) i^i Prime ) ) -> p e. RR+ ) |
| 9 | 8 | relogcld | |- ( ( A e. RR /\ p e. ( ( 0 [,] A ) i^i Prime ) ) -> ( log ` p ) e. RR ) |
| 10 | 8 | reeflogd | |- ( ( A e. RR /\ p e. ( ( 0 [,] A ) i^i Prime ) ) -> ( exp ` ( log ` p ) ) = p ) |
| 11 | 10 7 | eqeltrd | |- ( ( A e. RR /\ p e. ( ( 0 [,] A ) i^i Prime ) ) -> ( exp ` ( log ` p ) ) e. NN ) |
| 12 | 3 9 11 | efnnfsumcl | |- ( A e. RR -> ( exp ` sum_ p e. ( ( 0 [,] A ) i^i Prime ) ( log ` p ) ) e. NN ) |
| 13 | 2 12 | eqeltrd | |- ( A e. RR -> ( exp ` ( theta ` A ) ) e. NN ) |