abcabc Conjecture

OPENLandmarkConjectureProposed 1985 · Standard version

Canonical statement

For every ε>0\varepsilon>0, there is a constant Kε>0K_\varepsilon>0 such that, whenever coprime positive integers a,b,ca,b,c satisfy a+b=ca+b=c,
c<Kεrad(abc)1+ε,rad(n)=pnp. c<K_\varepsilon\,\operatorname{rad}(abc)^{1+\varepsilon},\qquad \operatorname{rad}(n)=\prod_{p\mid n}p.
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For every \(\varepsilon>0\), there is a constant \(K_\varepsilon>0\) such that, whenever coprime positive integers \(a,b,c\) satisfy \(a+b=c\),
\[
  c<K_\varepsilon\,\operatorname{rad}(abc)^{1+\varepsilon},\qquad
  \operatorname{rad}(n)=\prod_{p\mid n}p.
\]

The abcabc conjecture bounds the size of a coprime sum a+b=ca+b=c in terms of the distinct primes dividing abcabc. Masser's 1985 problem list is an early printed source [Masser1985ABC], and the conjecture has consequences throughout Diophantine analysis [Granville1998ABC]. Mochizuki's published IUT papers claim a proof [Mochizuki2021IUTIV], but the decisive compatibility step remains disputed [ScholzeStix2018ABC]. The catalog therefore records the canonical conjecture as open and links the claim audit rather than treating publication alone as resolution.

The boxed statement is the canonical open formulation — not a stronger variant or a related research program. The status reflects the catalog's last review; do your own literature search before investing serious effort.