let G be _Graph; :: thesis: G is GraphUnion of G .allComponents()
set G9 = the GraphUnion of G .allComponents() ;
G is GraphUnion of G .allSG() by Th35;
then A1: the GraphUnion of G .allComponents() is Subgraph of G by GLIBPRE1:119;
A2: now :: thesis: for v being Vertex of G ex H9 being Element of G .allComponents() st v in the_Vertices_of H9end;
now :: thesis: G is Subgraph of the GraphUnion of G .allComponents()
per cases ( G is edgeless or not G is edgeless ) ;
suppose not G is edgeless ; :: thesis: G is Subgraph of the GraphUnion of G .allComponents()
then reconsider G0 = G as non edgeless _Graph ;
now :: thesis: for e being Edge of G0 ex H9 being Element of G .allComponents() st createGraph e is Subgraph of H9end;
hence G is Subgraph of the GraphUnion of G .allComponents() by A2, Th23; :: thesis: verum
end;
end;
end;
hence G is GraphUnion of G .allComponents() by A1, GLIB_000:87, GLIB_014:22; :: thesis: verum