let X be finite set ; chromatic# (CompleteSGraph X) = card X
set n = card X;
set G = CompleteSGraph X;
set D = SmallestPartition X;
A1:
card (SmallestPartition X) = card X
by TOPGEN_2:12;
A2:
Vertices (CompleteSGraph X) = X
by Lm1;
reconsider D = SmallestPartition X as a_partition of Vertices (CompleteSGraph X) by Lm1;
A3:
D is StableSet-wise
for C being finite Coloring of (CompleteSGraph X) holds card X <= card C
proof
let C be
finite Coloring of
(CompleteSGraph X);
card X <= card C
assume A9:
card X > card C
;
contradiction
then
not
X is
empty
;
then consider p being
set ,
x,
y being
object such that A10:
p in C
and A11:
x in p
and A12:
y in p
and A13:
x <> y
by A9, A2, Th7;
A14:
p is
StableSet of
(CompleteSGraph X)
by A10, Def20;
reconsider p =
p as
Subset of
(Vertices (CompleteSGraph X)) by A10;
A15:
{x,y} nin CompleteSGraph X
by A14, A11, A12, A13, Def19;
p c= X
by A2;
hence
contradiction
by A11, A12, A15, Th34;
verum
end;
hence
chromatic# (CompleteSGraph X) = card X
by A1, A3, Def22; verum