FDL > PVS > Graphs > subgraphs > subgraph vert sub > pf:subgraph vert sub > 1 > 1 > 1 > 1 > 1 > 1 > 1

Conclusion

-1. V!1(x!1) = > vert(G!1)(x!1)

1. (vert(G!1)(x!1) AND V!1(x!1)) IFF V!1(x!1)