Induced subgraph on given vertices (keeps the given vertex order)
Subgraph[g, {v1, v2, …}]
Subgraph[g, {e1, e2, …}]
Subgraph[g, patt]
Subgraph[{v -> w, …}, …]
{g = PetersenGraph[5, 2], h = Subgraph[g, {1, 3, 4}]}
→ {Graph[<10>, <15>], Graph[<3>, <2>]}