let G be _finite _Graph; :: thesis: for L being MCS:Labeling of G
for x being set st not x in dom (L `1) & dom (L `1) <> the_Vertices_of G holds
(L `2) . x <= (L `2) . (MCS:PickUnnumbered L)

let L be MCS:Labeling of G; :: thesis: for x being set st not x in dom (L `1) & dom (L `1) <> the_Vertices_of G holds
(L `2) . x <= (L `2) . (MCS:PickUnnumbered L)

let x be set ; :: thesis: ( not x in dom (L `1) & dom (L `1) <> the_Vertices_of G implies (L `2) . x <= (L `2) . (MCS:PickUnnumbered L) )
assume that
A1: not x in dom (L `1) and
A2: dom (L `1) <> the_Vertices_of G ; :: thesis: (L `2) . x <= (L `2) . (MCS:PickUnnumbered L)
set VG = the_Vertices_of G;
set V2G = L `2 ;
set VLG = L `1 ;
set w = MCS:PickUnnumbered L;
consider S being non empty natural-membered finite set , F being Function such that
A3: S = rng F and
A4: F = (L `2) | ((the_Vertices_of G) \ (dom (L `1))) and
A5: MCS:PickUnnumbered L = the Element of F " {(max S)} by A2, Def19;
A6: dom F = (dom (L `2)) /\ ((the_Vertices_of G) \ (dom (L `1))) by A4, RELAT_1:61;
set y = max S;
max S in rng F by A3, XXREAL_2:def 8;
then A7: not F " {(max S)} is empty by FUNCT_1:72;
then MCS:PickUnnumbered L in dom F by A5, FUNCT_1:def 7;
then A8: (L `2) . (MCS:PickUnnumbered L) = F . (MCS:PickUnnumbered L) by A4, FUNCT_1:47;
F . (MCS:PickUnnumbered L) in {(max S)} by A5, A7, FUNCT_1:def 7;
then A9: (L `2) . (MCS:PickUnnumbered L) = max S by A8, TARSKI:def 1;
A10: dom (L `2) = the_Vertices_of G by FUNCT_2:def 1;
per cases ( x in the_Vertices_of G or not x in the_Vertices_of G ) ;
end;