Hard Problems That Quickly Become Very Easy

17 Dec 2020 · Barnaby Martin, Daniël Paulusma, Siani Smith ·

A graph class is hereditary if it is closed under vertex deletion. We give examples of NP-hard, PSPACE-complete and NEXPTIME-complete problems that become constant-time solvable for every hereditary graph class that is not equal to the class of all graphs.