let G2 be _Graph; for v, e, w being object
for G1 being addEdge 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 e in the_Edges_of G2 & not x in rng g2 & g2 is proper holds
g1 is proper
let v, e, w be object ; for G1 being addEdge 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 e in the_Edges_of G2 & not x in rng g2 & g2 is proper holds
g1 is proper
let G1 be addEdge 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 e in the_Edges_of G2 & not x in rng 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 e in the_Edges_of G2 & not x in rng g2 & g2 is proper holds
g1 is proper
let g2 be EColoring of G2; for x being object st g1 = g2 +* (e .--> x) & not e in the_Edges_of G2 & not x in rng g2 & g2 is proper holds
g1 is proper
let x be object ; ( g1 = g2 +* (e .--> x) & not e in the_Edges_of G2 & not x in rng g2 & g2 is proper implies g1 is proper )
assume A1:
( g1 = g2 +* (e .--> x) & not e in the_Edges_of G2 )
; ( x in rng g2 or not g2 is proper or g1 is proper )
assume A2:
( not x in rng g2 & g2 is proper )
; g1 is proper
dom (e .--> x) =
dom {[e,x]}
by FUNCT_4:82
.=
{e}
by RELAT_1:9
;
then
e in dom (e .--> x)
by TARSKI:def 1;
then
e in (dom g2) \/ (dom (e .--> x))
by XBOOLE_0:def 3;
then
e in dom g1
by A1, FUNCT_4:def 1;
then A3:
e in the_Edges_of G1
;
A4: rng (e .--> x) =
rng {[e,x]}
by FUNCT_4:82
.=
{x}
by RELAT_1:9
;
A5:
( v is Vertex of G2 & w is Vertex of G2 )
now for u1 being Vertex of G1 holds g1 | (u1 .edgesInOut()) is one-to-one let u1 be
Vertex of
G1;
g1 | (b1 .edgesInOut()) is one-to-one A6:
g1 | (u1 .edgesInOut()) = (g2 | (u1 .edgesInOut())) +* ((e .--> x) | (u1 .edgesInOut()))
by A1, FUNCT_4:71;
reconsider u2 =
u1 as
Vertex of
G2 by A1, A5, GLIB_006:def 11;
per cases
( ( u1 <> v & u1 <> w ) or u1 = v or u1 = w )
;
suppose A8:
(
u1 = v or
u1 = w )
;
g1 | (b1 .edgesInOut()) is one-to-one A9:
u1 .edgesInOut() = (u2 .edgesInOut()) \/ {e}
{e} misses the_Edges_of G2
by A1, ZFMISC_1:50;
then
{e} misses dom g2
by PARTFUN1:def 2;
then A10:
g2 | {e} = {}
by RELAT_1:66;
A11:
g2 | (u1 .edgesInOut()) =
(g2 | (u2 .edgesInOut())) \/ (g2 | {e})
by A9, RELAT_1:78
.=
g2 | (u2 .edgesInOut())
by A10
;
not
e in u2 .edgesInOut()
by A1;
then A12:
(e .--> x) | (u2 .edgesInOut()) = {}
by FUNCOP_1:76;
A13:
(e .--> x) | (u1 .edgesInOut()) =
((e .--> x) | (u2 .edgesInOut())) \/ ((e .--> x) | {e})
by A9, RELAT_1:78
.=
e .--> x
by A12
;
rng g2 misses rng (e .--> x)
by A2, A4, ZFMISC_1:50;
then A14:
rng (g2 | (u2 .edgesInOut())) misses rng (e .--> x)
by RELAT_1:70, XBOOLE_1:63;
A15:
g2 | (u2 .edgesInOut()) is
one-to-one
by A2;
g1 | (u1 .edgesInOut()) = (g2 | (u2 .edgesInOut())) +* (e .--> x)
by A6, A11, A13;
hence
g1 | (u1 .edgesInOut()) is
one-to-one
by A14, A15, FUNCT_4:92;
verum end; end; end;
hence
g1 is proper
; verum