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Description: The set of divisors of a number is a subset of a finite set. (Contributed by Mario Carneiro, 22-Sep-2014)
| Ref | Expression | ||
|---|---|---|---|
| Assertion | dvdsssfz1 | |- ( A e. NN -> { p e. NN | p || A } C_ ( 1 ... A ) ) |
| Step | Hyp | Ref | Expression |
|---|---|---|---|
| 1 | nnz | |- ( p e. NN -> p e. ZZ ) |
|
| 2 | id | |- ( A e. NN -> A e. NN ) |
|
| 3 | dvdsle | |- ( ( p e. ZZ /\ A e. NN ) -> ( p || A -> p <_ A ) ) |
|
| 4 | 1 2 3 | syl2anr | |- ( ( A e. NN /\ p e. NN ) -> ( p || A -> p <_ A ) ) |
| 5 | ibar | |- ( p e. NN -> ( p <_ A <-> ( p e. NN /\ p <_ A ) ) ) |
|
| 6 | 5 | adantl | |- ( ( A e. NN /\ p e. NN ) -> ( p <_ A <-> ( p e. NN /\ p <_ A ) ) ) |
| 7 | nnz | |- ( A e. NN -> A e. ZZ ) |
|
| 8 | 7 | adantr | |- ( ( A e. NN /\ p e. NN ) -> A e. ZZ ) |
| 9 | fznn | |- ( A e. ZZ -> ( p e. ( 1 ... A ) <-> ( p e. NN /\ p <_ A ) ) ) |
|
| 10 | 8 9 | syl | |- ( ( A e. NN /\ p e. NN ) -> ( p e. ( 1 ... A ) <-> ( p e. NN /\ p <_ A ) ) ) |
| 11 | 6 10 | bitr4d | |- ( ( A e. NN /\ p e. NN ) -> ( p <_ A <-> p e. ( 1 ... A ) ) ) |
| 12 | 4 11 | sylibd | |- ( ( A e. NN /\ p e. NN ) -> ( p || A -> p e. ( 1 ... A ) ) ) |
| 13 | 12 | ralrimiva | |- ( A e. NN -> A. p e. NN ( p || A -> p e. ( 1 ... A ) ) ) |
| 14 | rabss | |- ( { p e. NN | p || A } C_ ( 1 ... A ) <-> A. p e. NN ( p || A -> p e. ( 1 ... A ) ) ) |
|
| 15 | 13 14 | sylibr | |- ( A e. NN -> { p e. NN | p || A } C_ ( 1 ... A ) ) |