Problems
Everything in the archive: the problem as it was posed, what has been attempted against it, and who checked each attempt. The mark down the left of the list says who has looked — a person, a machine, or nobody yet. Human reviews and machine checks are counted separately and are never added together.
1 problem
showing 1–1
A graph is K 5-friendly if and only if it does not contain any of K_6,C_7^2 and DW_5 as a minor.