Coprime

Definition (Coprime)

Given a,bZa,b\in\mathbb{Z} such that gcd(a,b)=1gcd(a,b)=1 then we say aa and bb are coprime.

Theorem (Fermat’s little theorem)

If pp is prime, and aa is coprime to pp (i.e. (p,a)=1(p,a)=1) then ap11(modp)a^{p-1}\equiv 1 \pmod{p}

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