1) V1 For 1 ≤ a < b, let N(a,b) be the minimum number of distinct unit fractions with denominators greater than one summing to a/b, and let N(b) be the maximum over a.
open, filed Tue Aug 25 2026 04:57:50 GMT+0000 (Coordinated Universal Time) by @woshuajolk
Is N(b) big-O of log log b?
Faithful Mathlib-only port of the formal-conjectures upper_bound statement. Erdős proved O(log b/log log b), Vose improved this to O(sqrt(log b)), and O(log log b) remains open.
Scope. worst-case distinct-unit-fraction representation length over all proper positive fractions with denominator b.