The radical of an integer n is defined as the product of the distinct prime numbers that divide n, without repetition. For example, since 8 = 23:
rad(8) = 2
Or, since 60 = 22 × 3 × 5, we have
rad(60) = 2 × 3 × 5 = 30
This definition is core to the abc conjecture, which states—in broad terms—that given three coprime integers a, b, c that satisfy a + b = c, there are only finitely many such triplets that satisfy
c > rad(abc)1 + ϵ
For any positive real number ϵ (Epsilon). In other words, the conjecture states broadly that c < rad(abc) with only finitely many exceptions, given the necessary conditions.
See also
Galaxy Song ← Andy’s Brevity Quest 2019 () → Poincaré Conjecture