 Solution

ID: past-exam-of-the-probability-statistics-and-options-i-course-of-the-university-of-oxford/2009/c/1/i/solution

p

and any integer

a

a^{p} \equiv a (mod p) .

p ∤ a

, the equivalent multiplicative form is

a^{p - 1} \equiv 1 (mod p)

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