The WaltherGraph command creates the Walther graph.

The Walther graph is a graph with 25 vertices and 31 edges.

$\mathrm{with}\left(\mathrm{GraphTheory}\right)\:$

$\mathrm{with}\left(\mathrm{SpecialGraphs}\right)\:$

$\mathrm{WG}≔\mathrm{WaltherGraph}\left(\right)$

$\mathrm{WG}≔\mathrm{Graph\; 1:\; an\; undirected\; graph\; with\; 25\; vertices\; and\; 31\; edge(s)}$

$\mathrm{ChromaticIndex}\left(\mathrm{WG}\right)$

$3$

"Walther graph", Wikipedia. http://en.wikipedia.org/wiki/Walther_graph

The GraphTheory[SpecialGraphs][WaltherGraph] command was introduced in Maple 2021.

For more information on Maple 2021 changes, see Updates in Maple 2021.