A density bound for triangle-free 4-critical graphs [article]

Benjamin Moore, Evelyne Smith-Roberge
2022 arXiv   pre-print
We show every triangle-free 4-critical graph G satisfies e(G) ≥5v(G)+2/3. In fact, we prove a more general result characterizing sparse 4-critical graphs with few vertex- disjoint triangles.
arXiv:2012.01503v2 fatcat:hvew363qzzap5nqf4jbodmpe6u