$S$-packing chromatic vertex-critical graphs

Přemysl Holub, Marko Jakovac, Sandi Klavžar

For a non-decreasing sequence of positive integers $S=(s_1,s_2,\dots )$, the {\em $S$-packing chromatic number} ${\chi }_S(G)$ of $G$ is the smallest integer $k$ such that the vertex s…