Configuration families certifying the four color theorem

Jude Gomila, Dan Romik, John Steinberger2026-11-07

We report an unavoidable set of $N = 619$ reducible configurations certifying the four color theorem in the framework of Robertson, Sanders, Seymour and Thomas (RSST) [1], improving on their $633$. We call it K619. The family $619 = 244$ $D$-reducible $+\ 375$ $C$-reducible…