now per cases
( ( V is non empty Subset of (the_Vertices_of G) & E c= G .edgesBetween V ) or not V is non empty Subset of (the_Vertices_of G) or not E c= G .edgesBetween V )
;
suppose A1:
(
V is non
empty Subset of
(the_Vertices_of G) &
E c= G .edgesBetween V )
;
ex GG being [ELabeled] inducedSubgraph of G,V,E st GG is elabel-inheriting consider X being
[ELabeled] inducedSubgraph of
G,
V,
E;
set EL =
(the_ELabel_of G) | (the_Edges_of X);
reconsider EL9 =
(the_ELabel_of G) | (the_Edges_of X) as
PartFunc of
(dom ((the_ELabel_of G) | (the_Edges_of X))),
(rng ((the_ELabel_of G) | (the_Edges_of X))) by RELSET_1:11;
reconsider EL9 =
EL9 as
PartFunc of
(the_Edges_of X),
(rng ((the_ELabel_of G) | (the_Edges_of X))) by RELAT_1:87, RELSET_1:13;
set GG =
X .set ELabelSelector ,
EL9;
A2:
X .set ELabelSelector ,
EL9 == X
by Lm3;
then
X .set ELabelSelector ,
EL9 is
Subgraph of
X
by GLIB_000:90;
then reconsider GG =
X .set ELabelSelector ,
EL9 as
Subgraph of
G by GLIB_000:46;
A3:
the_Vertices_of GG =
the_Vertices_of X
by A2, GLIB_000:def 36
.=
V
by A1, GLIB_000:def 39
;
the_Edges_of GG =
the_Edges_of X
by A2, GLIB_000:def 36
.=
E
by A1, GLIB_000:def 39
;
then reconsider GG =
GG as
[ELabeled] inducedSubgraph of
G,
V,
E by A1, A3, GLIB_000:def 39;
take GG =
GG;
GG is elabel-inheriting the_ELabel_of GG =
(the_ELabel_of G) | (the_Edges_of X)
by GLIB_000:11
.=
(the_ELabel_of G) | (the_Edges_of GG)
by A2, GLIB_000:def 36
;
hence
GG is
elabel-inheriting
by Def11;
verum end; end; end;
hence
ex b1 being [ELabeled] inducedSubgraph of G,V,E st b1 is elabel-inheriting
; verum