let G be _Graph; 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;
now G is Subgraph of the GraphUnion of G .allComponents() per cases
( G is edgeless or not G is edgeless )
;
suppose
not
G is
edgeless
;
G is Subgraph of the GraphUnion of G .allComponents() then reconsider G0 =
G as non
edgeless _Graph ;
now for e being Edge of G0 ex H9 being Element of G .allComponents() st createGraph e is Subgraph of H9let e be
Edge of
G0;
ex H9 being Element of G .allComponents() st createGraph e is Subgraph of H9set v =
(the_Source_of G) . e;
set w =
(the_Target_of G) . e;
e DJoins (the_Source_of G) . e,
(the_Target_of G) . e,
createGraph e
by Th14;
then
e Joins (the_Source_of G) . e,
(the_Target_of G) . e,
createGraph e
by GLIB_000:16;
then A3:
e Joins (the_Source_of G) . e,
(the_Target_of G) . e,
G
by GLIB_000:72;
then reconsider v =
(the_Source_of G) . e,
w =
(the_Target_of G) . e as
Vertex of
G by GLIB_000:13;
set H9 = the
plain inducedSubgraph of
G,
(G .reachableFrom v);
reconsider H9 = the
plain inducedSubgraph of
G,
(G .reachableFrom v) as
Element of
G .allComponents() by Th189;
take H9 =
H9;
createGraph e is Subgraph of H9A4:
the_Vertices_of H9 = G .reachableFrom v
by GLIB_000:def 37;
then A5:
v in the_Vertices_of H9
by GLIB_002:9;
then A6:
w in the_Vertices_of H9
by A3, A4, GLIB_002:10;
then
e in G .edgesBetween (the_Vertices_of H9)
by A3, A5, GLIB_000:32;
then
e in the_Edges_of H9
by A4, GLIB_000:def 37;
then
{e} c= the_Edges_of H9
by ZFMISC_1:31;
then A7:
the_Edges_of (createGraph e) c= the_Edges_of H9
by Th13;
{v,w} c= the_Vertices_of H9
by A5, A6, ZFMISC_1:32;
then
the_Vertices_of (createGraph e) c= the_Vertices_of H9
by Th13;
hence
createGraph e is
Subgraph of
H9
by A7, GLIB_000:44;
verum end; hence
G is
Subgraph of the
GraphUnion of
G .allComponents()
by A2, Th23;
verum end; end; end;
hence
G is GraphUnion of G .allComponents()
by A1, GLIB_000:87, GLIB_014:22; verum