A counterexample to the rank‐coloring conjecture
N. Alon, Paul D. Seymour · Journal of Graph Theory · 1989
Abstract It has been conjectured by C. van Nuffelen that the chromatic number of any graph with at least one edge does not exceed the rank of its adjacency matrix. We give a counterexample, with chromatic number 32 and with an adjacency matrix of rank 29.