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Ed Quanta
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Let n be a natural number. I have to prove that n is prime if and only if (n-1)! is congruent to -1modn.
I am supposed to group the equivalence classes of factors of (n-1)! into pairs {a,a^-1). This I find to be confusing. Help anyone?
I am supposed to group the equivalence classes of factors of (n-1)! into pairs {a,a^-1). This I find to be confusing. Help anyone?