let V be non empty set ; for E being symmetric Relation of V
for G being GraphFromSymRel of V,E holds VertexAdjSymRel G = E
let E be symmetric Relation of V; for G being GraphFromSymRel of V,E holds VertexAdjSymRel G = E
let G be GraphFromSymRel of V,E; VertexAdjSymRel G = E
now for x, y being object holds
( ( [x,y] in VertexAdjSymRel G implies [x,y] in E ) & ( [x,y] in E implies [x,y] in VertexAdjSymRel G ) )let x,
y be
object ;
( ( [x,y] in VertexAdjSymRel G implies [x,y] in E ) & ( [x,y] in E implies [x,y] in VertexAdjSymRel G ) )set G0 =
createGraph (
V,
E);
consider E0 being
RepEdgeSelection of
createGraph (
V,
E)
such that A2:
G is
inducedSubgraph of
createGraph (
V,
E),
the_Vertices_of (createGraph (V,E)),
E0
by GLIB_009:def 7;
A3:
the_Edges_of (createGraph (V,E)) = (createGraph (V,E)) .edgesBetween (the_Vertices_of (createGraph (V,E)))
by GLIB_000:34;
the_Vertices_of (createGraph (V,E)) c= the_Vertices_of (createGraph (V,E))
;
then A4:
the_Vertices_of G =
the_Vertices_of (createGraph (V,E))
by A2, A3, GLIB_000:def 37
.=
V
;
assume A5:
[x,y] in E
;
[x,y] in VertexAdjSymRel Gthen reconsider v =
x,
w =
y as
Vertex of
G by A4, ZFMISC_1:87;
v,
w are_adjacent
by A5, Th89;
hence
[x,y] in VertexAdjSymRel G
by Th33;
verum end;
hence
VertexAdjSymRel G = E
by RELAT_1:def 2; verum