let G2 be _Graph; for v being Vertex of G2
for e, w being object
for G1 being addAdjVertex of G2,v,e,w
for g being EColoring of G2
for x being object st not e in the_Edges_of G2 & not w in the_Vertices_of G2 holds
g +* (e .--> x) is EColoring of G1
let v be Vertex of G2; for e, w being object
for G1 being addAdjVertex of G2,v,e,w
for g being EColoring of G2
for x being object st not e in the_Edges_of G2 & not w in the_Vertices_of G2 holds
g +* (e .--> x) is EColoring of G1
let e, w be object ; for G1 being addAdjVertex of G2,v,e,w
for g being EColoring of G2
for x being object st not e in the_Edges_of G2 & not w in the_Vertices_of G2 holds
g +* (e .--> x) is EColoring of G1
let G1 be addAdjVertex of G2,v,e,w; for g being EColoring of G2
for x being object st not e in the_Edges_of G2 & not w in the_Vertices_of G2 holds
g +* (e .--> x) is EColoring of G1
let g be EColoring of G2; for x being object st not e in the_Edges_of G2 & not w in the_Vertices_of G2 holds
g +* (e .--> x) is EColoring of G1
let x be object ; ( not e in the_Edges_of G2 & not w in the_Vertices_of G2 implies g +* (e .--> x) is EColoring of G1 )
assume A1:
( not e in the_Edges_of G2 & not w in the_Vertices_of G2 )
; g +* (e .--> x) is EColoring of G1
A2: dom (e .--> x) =
dom {[e,x]}
by FUNCT_4:82
.=
{e}
by RELAT_1:9
;
dom (g +* (e .--> x)) =
(dom g) \/ (dom (e .--> x))
by FUNCT_4:def 1
.=
(the_Edges_of G2) \/ {e}
by A2, PARTFUN1:def 2
.=
the_Edges_of G1
by A1, GLIB_006:def 12
;
hence
g +* (e .--> x) is EColoring of G1
by RELAT_1:def 18, PARTFUN1:def 2; verum