| 35849 |      1 | (*  Author: Clemens Ballarin, started 5 October 1999
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|  |      2 | 
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|  |      3 | Principle ideal domains.
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| 7998 |      4 | *)
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|  |      5 | 
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| 35849 |      6 | theory PID
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|  |      7 | imports Ideal2
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|  |      8 | begin
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| 7998 |      9 | 
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| 17479 |     10 | instance pid < factorial
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|  |     11 |   apply intro_classes
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|  |     12 |   apply (erule pid_irred_imp_prime)
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|  |     13 |   done
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| 7998 |     14 | 
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|  |     15 | end
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