let V be set ; for c being Cardinal
for G2 being b1 -ecolorable _Graph
for v being object
for G1 being addAdjVertexAll of G2,v,V holds G1 is c +` (card V) -ecolorable
let c be Cardinal; for G2 being c -ecolorable _Graph
for v being object
for G1 being addAdjVertexAll of G2,v,V holds G1 is c +` (card V) -ecolorable
let G2 be c -ecolorable _Graph; for v being object
for G1 being addAdjVertexAll of G2,v,V holds G1 is c +` (card V) -ecolorable
let v be object ; for G1 being addAdjVertexAll of G2,v,V holds G1 is c +` (card V) -ecolorable
let G1 be addAdjVertexAll of G2,v,V; G1 is c +` (card V) -ecolorable
per cases
( ( not v in the_Vertices_of G2 & V c= the_Vertices_of G2 ) or v in the_Vertices_of G2 or not V c= the_Vertices_of G2 )
;
suppose A1:
( not
v in the_Vertices_of G2 &
V c= the_Vertices_of G2 )
;
G1 is c +` (card V) -ecolorable consider g2 being
proper EColoring of
G2 such that A2:
card (rng g2) c= c
by Def6;
consider E0 being
set such that A3:
(
card V = card E0 &
E0 misses the_Edges_of G2 )
and A4:
the_Edges_of G1 = (the_Edges_of G2) \/ E0
and
for
v1 being
object st
v1 in V holds
ex
e1 being
object st
(
e1 in E0 &
e1 Joins v1,
v,
G1 & ( for
e2 being
object st
e2 Joins v1,
v,
G1 holds
e1 = e2 ) )
by A1, GLIB_007:def 4;
set E =
G1 .edgesBetween (
V,
{v});
set h =
<:((G1 .edgesBetween (V,{v})) --> (rng g2)),(id (G1 .edgesBetween (V,{v}))):>;
set g1 =
g2 +* <:((G1 .edgesBetween (V,{v})) --> (rng g2)),(id (G1 .edgesBetween (V,{v}))):>;
A5:
G1 .edgesBetween (
V,
{v})
= E0
by A1, A3, A4, GLIB_007:58;
dom <:((G1 .edgesBetween (V,{v})) --> (rng g2)),(id (G1 .edgesBetween (V,{v}))):> = G1 .edgesBetween (
V,
{v})
by Lm8;
then reconsider g1 =
g2 +* <:((G1 .edgesBetween (V,{v})) --> (rng g2)),(id (G1 .edgesBetween (V,{v}))):> as
EColoring of
G1 by A1, Th82;
reconsider g1 =
g1 as
proper EColoring of
G1 by A1, Th96;
card (rng g1) c= card ((rng g2) \/ (rng <:((G1 .edgesBetween (V,{v})) --> (rng g2)),(id (G1 .edgesBetween (V,{v}))):>))
by FUNCT_4:17, CARD_1:11;
then A6:
card (rng g1) c= (card (rng g2)) +` (card (rng <:((G1 .edgesBetween (V,{v})) --> (rng g2)),(id (G1 .edgesBetween (V,{v}))):>))
by Lm11, CARD_2:35;
card (rng <:((G1 .edgesBetween (V,{v})) --> (rng g2)),(id (G1 .edgesBetween (V,{v}))):>) =
card [:{(rng g2)},(G1 .edgesBetween (V,{v})):]
by Lm10
.=
card [:(G1 .edgesBetween (V,{v})),{(rng g2)}:]
by CARD_2:4
.=
card V
by A3, A5, CARD_1:69
;
then
(card (rng g2)) +` (card (rng <:((G1 .edgesBetween (V,{v})) --> (rng g2)),(id (G1 .edgesBetween (V,{v}))):>)) c= c +` (card V)
by A2, CARD_2:84;
hence
G1 is
c +` (card V) -ecolorable
by A6, XBOOLE_1:1;
verum end; end;