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 g1 being EColoring of G1
for g2 being EColoring of G2
for x being object st g1 = g2 +* (e .--> x) & not x in rng g2 & not e in the_Edges_of G2 & not w in the_Vertices_of G2 & g2 is proper holds
g1 is proper
let v be Vertex of G2; for e, w being object
for G1 being addAdjVertex of G2,v,e,w
for g1 being EColoring of G1
for g2 being EColoring of G2
for x being object st g1 = g2 +* (e .--> x) & not x in rng g2 & not e in the_Edges_of G2 & not w in the_Vertices_of G2 & g2 is proper holds
g1 is proper
let e, w be object ; for G1 being addAdjVertex of G2,v,e,w
for g1 being EColoring of G1
for g2 being EColoring of G2
for x being object st g1 = g2 +* (e .--> x) & not x in rng g2 & not e in the_Edges_of G2 & not w in the_Vertices_of G2 & g2 is proper holds
g1 is proper
let G1 be addAdjVertex of G2,v,e,w; for g1 being EColoring of G1
for g2 being EColoring of G2
for x being object st g1 = g2 +* (e .--> x) & not x in rng g2 & not e in the_Edges_of G2 & not w in the_Vertices_of G2 & g2 is proper holds
g1 is proper
let g1 be EColoring of G1; for g2 being EColoring of G2
for x being object st g1 = g2 +* (e .--> x) & not x in rng g2 & not e in the_Edges_of G2 & not w in the_Vertices_of G2 & g2 is proper holds
g1 is proper
let g2 be EColoring of G2; for x being object st g1 = g2 +* (e .--> x) & not x in rng g2 & not e in the_Edges_of G2 & not w in the_Vertices_of G2 & g2 is proper holds
g1 is proper
let x be object ; ( g1 = g2 +* (e .--> x) & not x in rng g2 & not e in the_Edges_of G2 & not w in the_Vertices_of G2 & g2 is proper implies g1 is proper )
assume that
A1:
( g1 = g2 +* (e .--> x) & not x in rng g2 )
and
A2:
( not e in the_Edges_of G2 & not w in the_Vertices_of G2 )
and
A3:
g2 is proper
; g1 is proper
consider G9 being addVertex of G2,w such that
A4:
G1 is addEdge of G9,v,e,w
by A2, GLIB_006:125;
A5:
the_Edges_of G9 = the_Edges_of G2
by GLIB_006:def 10;
then reconsider g9 = g2 as EColoring of G9 ;
g9 is proper
by A3, Th92;
hence
g1 is proper
by A1, A2, A4, A5, Th93; verum