Problems / combinatorics
combinatorics / Additive combinatorics
Lower bound 0.38055470 for Erdős's minimum overlap constant
A rigorous lower bound c>0.38055470, improving White's 0.379005 (2022). The problem stays open: the best public upper bound is 0.3808585749 (Einstein Arena, August 2026; 0.380868 in the literature, SimpleTES), so c is now known to within about 3×10−4. The bound rests on a finite certificate checked in ball arithmetic plus a step-function transfer from the continuous to the finite problem. The later Station paper (arXiv 2608.23691) reaches 0.380552, below this; a higher claim of 0.3805634 posted to the tracker on 19 September is unchecked.