The HigmanSimsGraph command creates the Higman-Sims graph, a 22-regular graph with 100 vertices and 1100 edges.

The automorphism group of the Higman-Sims graph contains the Higman-Sims group as a subgroup of index 2.

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

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

$\mathrm{HS}≔\mathrm{HigmanSimsGraph}\left(\right)$

$\mathrm{HS}≔\mathrm{Graph\; 1:\; an\; undirected\; graph\; with\; 100\; vertices\; and\; 1100\; edge(s)}$

$\mathrm{IsStronglyRegular}\left(\mathrm{HS}\,'\mathrm{parameters}'\right)$

$\mathrm{true},\left[22\,0\,6\right]$

$\mathrm{ChromaticNumber}\left(\mathrm{HS}\right)$

$6$

"Higman-Sims graph", Wikipedia. http://en.wikipedia.org/wiki/Higman-Sims_graph

The GraphTheory[SpecialGraphs][HigmanSimsGraph] command was introduced in Maple 2020.

For more information on Maple 2020 changes, see Updates in Maple 2020.