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(*<*)
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theory prime_def = Main:;
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consts prime :: "nat \\<Rightarrow> bool"
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(*>*)
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(*<*)term(*>*)
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"prime(p) \\<equiv> 1 < p \\<and> (m dvd p \\<longrightarrow> (m=1 \\<or> m=p))";
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text{*\noindent\small
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where \isa{dvd} means ``divides''.
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Isabelle rejects this ``definition'' because of the extra \isa{m} on the
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right-hand side, which would introduce an inconsistency (why?). What you
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should have written is
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*}
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(*<*)term(*>*)
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"prime(p) \\<equiv> 1 < p \\<and> (\\<forall>m. m dvd p \\<longrightarrow> (m=1 \\<or> m=p))"
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(*<*)
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end
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(*>*)
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