let G2 be removeDParallelEdges of G; G2 is loopfull
consider E being RepDEdgeSelection of G such that
A5:
G2 is inducedSubgraph of G, the_Vertices_of G,E
by GLIB_009:def 8;
now for v being Vertex of G2 ex e being object st e DJoins v,v,G2let v be
Vertex of
G2;
ex e being object st e DJoins v,v,G2
v is
Vertex of
G
by GLIB_000:def 33;
then consider e0 being
object such that A6:
e0 DJoins v,
v,
G
by Th1;
consider e being
object such that A7:
(
e DJoins v,
v,
G &
e in E )
and
for
e9 being
object st
e9 DJoins v,
v,
G &
e9 in E holds
e9 = e
by A6, GLIB_009:def 6;
take e =
e;
e DJoins v,v,G2
E c= the_Edges_of G
;
then A8:
E c= G .edgesBetween (the_Vertices_of G)
by GLIB_000:34;
the_Vertices_of G c= the_Vertices_of G
;
then
the_Edges_of G2 = E
by A5, A8, GLIB_000:def 37;
hence
e DJoins v,
v,
G2
by A7, GLIB_000:73;
verum end;
hence
G2 is loopfull
by Th1; verum