Probabilistic Primality Testing

FLT: am-1 = 1 mod m, for m prime (*)

For most composite numbers, equation false for more than half the a’s.

Gives way to test a number m to see if it’s prime.

Choose a random 1<= a <= m-1.

Raise it to power m-1 to see if equation (*) is true.

If not, m isn’t prime.

If is, repeat with bunch more random a’s.

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