Circular coloring and fractional coloring in planar graphs
Circular coloring and fractional coloring in planar graphs
Abstract We study the following Steinberg‐type problem on circular coloring: for an odd integer , what is the smallest number such that every planar graph of girth without cycles of length from to admits a homomorphism to the odd cycle (or equivalently, is circular ‐colorable). Known results and counterexamples on …