Arc-Density Lower Bound for Pushably 3‑Critical Oriented Graphs
Any pushably 3‑critical oriented graph on n vertices needs at least (15n + 2)⁄13 arcs. If a graph’s max average degree < 30⁄13 and girth ≥5, its pushable chromatic number ≤3. getnews.me/arc-density-lower-bound-... #pushablecolours #orientedgraphs