The IsSubgraphIsomorphic command accepts either two undirected graphs or two directed graphs as input.  It returns true if G1 is isomorphic to some subgraph of G2.

If the graphs are weighted graphs, the edge weights are ignored.

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

$\mathrm{C6}≔\mathrm{CycleGraph}\left(6\right)$

$\mathrm{C6}≔\mathrm{Graph\; 1:\; an\; undirected\; unweighted\; graph\; with\; 6\; vertices\; and\; 6\; edge(s)}$

$\mathrm{K24}≔\mathrm{CompleteGraph}\left(2\,4\right)$

$\mathrm{K24}≔\mathrm{Graph\; 2:\; an\; undirected\; unweighted\; graph\; with\; 6\; vertices\; and\; 8\; edge(s)}$

$\mathrm{K33}≔\mathrm{CompleteGraph}\left(3\,3\right)$

$\mathrm{K33}≔\mathrm{Graph\; 3:\; an\; undirected\; unweighted\; graph\; with\; 6\; vertices\; and\; 9\; edge(s)}$

$\mathrm{IsSubgraphIsomorphic}\left(\mathrm{C6}\,\mathrm{K33}\right)$

$\mathrm{true}$

$\mathrm{IsSubgraphIsomorphic}\left(\mathrm{C6}\,\mathrm{K24}\right)$

$\mathrm{false}$

The GraphTheory[IsSubgraphIsomorphic] command was introduced in Maple 2021.

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