let G2 be _Graph; for v being Vertex of G2
for e, w, x being object
for G1 being addAdjVertex of G2,v,e,w
for f being VColoring of G2 st not e in the_Edges_of G2 & not w in the_Vertices_of G2 holds
f +* (w .--> x) is VColoring of G1
let v be Vertex of G2; for e, w, x being object
for G1 being addAdjVertex of G2,v,e,w
for f being VColoring of G2 st not e in the_Edges_of G2 & not w in the_Vertices_of G2 holds
f +* (w .--> x) is VColoring of G1
let e, w, x be object ; for G1 being addAdjVertex of G2,v,e,w
for f being VColoring of G2 st not e in the_Edges_of G2 & not w in the_Vertices_of G2 holds
f +* (w .--> x) is VColoring of G1
let G1 be addAdjVertex of G2,v,e,w; for f being VColoring of G2 st not e in the_Edges_of G2 & not w in the_Vertices_of G2 holds
f +* (w .--> x) is VColoring of G1
let f be VColoring of G2; ( not e in the_Edges_of G2 & not w in the_Vertices_of G2 implies f +* (w .--> x) is VColoring of G1 )
assume
( not e in the_Edges_of G2 & not w in the_Vertices_of G2 )
; f +* (w .--> x) is VColoring of G1
then the_Vertices_of G1 =
(the_Vertices_of G2) \/ {w}
by GLIB_006:def 12
.=
(dom f) \/ {w}
by PARTFUN1:def 2
.=
(dom f) \/ (dom {[w,x]})
by RELAT_1:9
.=
(dom f) \/ (dom (w .--> x))
by FUNCT_4:82
.=
dom (f +* (w .--> x))
by FUNCT_4:def 1
;
hence
f +* (w .--> x) is VColoring of G1
by RELAT_1:def 18, PARTFUN1:def 2; verum