FindIsomorphicSubgraph
FindIsomorphicSubgraph[g1,g2] finds a subgraph of g1 that is isomorphic to g2.
FindIsomorphicSubgraph[g1,g2,n] finds at most n subgraphs.
Examples
(* Find a triangle subgraph *)
g = RandomGraph[{10, 20}];
triangle = CycleGraph[3];
FindIsomorphicSubgraph[g, triangle]
(* Find multiple matching subgraphs *)
FindIsomorphicSubgraph[g, triangle, 5]Please visit the official Wolfram Language Reference for more details.