set v = (the_Source_of G) . e;
set w = (the_Target_of G) . e;
reconsider V = {((the_Source_of G) . e),((the_Target_of G) . e)} as non empty Subset of (the_Vertices_of G) ;
set S = e .--> ((the_Source_of G) . e);
set T = e .--> ((the_Target_of G) . e);
( dom (e .--> ((the_Source_of G) . e)) = dom {[e,((the_Source_of G) . e)]} & dom (e .--> ((the_Target_of G) . e)) = dom {[e,((the_Target_of G) . e)]} )
by FUNCT_4:82;
then A1:
( dom (e .--> ((the_Source_of G) . e)) = {e} & dom (e .--> ((the_Target_of G) . e)) = {e} )
by RELAT_1:9;
( rng (e .--> ((the_Source_of G) . e)) = {((the_Source_of G) . e)} & rng (e .--> ((the_Target_of G) . e)) = {((the_Target_of G) . e)} )
by FUNCOP_1:88;
then reconsider S = e .--> ((the_Source_of G) . e), T = e .--> ((the_Target_of G) . e) as Function of {e},V by A1, ZFMISC_1:7, FUNCT_2:2;
set H = createGraph (V,{e},S,T);
now ( the_Vertices_of (createGraph (V,{e},S,T)) c= the_Vertices_of G & the_Edges_of (createGraph (V,{e},S,T)) c= the_Edges_of G & ( for e0 being set st e0 in the_Edges_of (createGraph (V,{e},S,T)) holds
( (the_Source_of (createGraph (V,{e},S,T))) . e0 = (the_Source_of G) . e0 & (the_Target_of (createGraph (V,{e},S,T))) . e0 = (the_Target_of G) . e0 ) ) )thus
(
the_Vertices_of (createGraph (V,{e},S,T)) c= the_Vertices_of G &
the_Edges_of (createGraph (V,{e},S,T)) c= the_Edges_of G )
;
for e0 being set st e0 in the_Edges_of (createGraph (V,{e},S,T)) holds
( (the_Source_of (createGraph (V,{e},S,T))) . e0 = (the_Source_of G) . e0 & (the_Target_of (createGraph (V,{e},S,T))) . e0 = (the_Target_of G) . e0 )let e0 be
set ;
( e0 in the_Edges_of (createGraph (V,{e},S,T)) implies ( (the_Source_of (createGraph (V,{e},S,T))) . e0 = (the_Source_of G) . e0 & (the_Target_of (createGraph (V,{e},S,T))) . e0 = (the_Target_of G) . e0 ) )assume
e0 in the_Edges_of (createGraph (V,{e},S,T))
;
( (the_Source_of (createGraph (V,{e},S,T))) . e0 = (the_Source_of G) . e0 & (the_Target_of (createGraph (V,{e},S,T))) . e0 = (the_Target_of G) . e0 )then A2:
e0 = e
by TARSKI:def 1;
thus
(the_Source_of (createGraph (V,{e},S,T))) . e0 = (the_Source_of G) . e0
by A2, FUNCOP_1:72;
(the_Target_of (createGraph (V,{e},S,T))) . e0 = (the_Target_of G) . e0thus
(the_Target_of (createGraph (V,{e},S,T))) . e0 = (the_Target_of G) . e0
by A2, FUNCOP_1:72;
verum end;
then reconsider H = createGraph (V,{e},S,T) as plain Subgraph of G by GLIB_000:def 32;
take
H
; ex V being non empty Subset of (the_Vertices_of G) ex S, T being Function of {e},V st
( H = createGraph (V,{e},S,T) & {((the_Source_of G) . e),((the_Target_of G) . e)} = V & S = e .--> ((the_Source_of G) . e) & T = e .--> ((the_Target_of G) . e) )
take
V
; ex S, T being Function of {e},V st
( H = createGraph (V,{e},S,T) & {((the_Source_of G) . e),((the_Target_of G) . e)} = V & S = e .--> ((the_Source_of G) . e) & T = e .--> ((the_Target_of G) . e) )
take
S
; ex T being Function of {e},V st
( H = createGraph (V,{e},S,T) & {((the_Source_of G) . e),((the_Target_of G) . e)} = V & S = e .--> ((the_Source_of G) . e) & T = e .--> ((the_Target_of G) . e) )
take
T
; ( H = createGraph (V,{e},S,T) & {((the_Source_of G) . e),((the_Target_of G) . e)} = V & S = e .--> ((the_Source_of G) . e) & T = e .--> ((the_Target_of G) . e) )
thus
( H = createGraph (V,{e},S,T) & {((the_Source_of G) . e),((the_Target_of G) . e)} = V & S = e .--> ((the_Source_of G) . e) & T = e .--> ((the_Target_of G) . e) )
; verum