ABC CONJECTURE
a+b=c, hcf(a, b)=1, c<=C_0rad(abc)
Disproof:a=1c<=C_0rad(abc) = C_0rad((c-1)c)[let c->999999...]->C_0rad(c^2) = C_0rad(c)But c<=C_0rad(c) - clearly no bounds on C_0.