A coloring c of a graph G = (V,E) is a b-coloring if in every color class there is a vertex colored i whose neighborhood intersects every other color classes. The b-chromatic number of G, denoted χb(G), is the greatest integer k such that G admits a b-coloring with k colors. A graph G is tight if it has exactly m(G) vertices of degree m(G)−1, where m(G) is the largest integer m such that G has ...