let G be _Graph; the_Vertices_of (G .allComponents()) = G .componentSet()
now for V being object holds
( ( V in G .componentSet() implies ex C being _Graph st
( C in G .allComponents() & V = the_Vertices_of C ) ) & ( ex C being _Graph st
( C in G .allComponents() & V = the_Vertices_of C ) implies V in G .componentSet() ) )let V be
object ;
( ( V in G .componentSet() implies ex C being _Graph st
( C in G .allComponents() & V = the_Vertices_of C ) ) & ( ex C being _Graph st
( C in G .allComponents() & V = the_Vertices_of C ) implies V in G .componentSet() ) )given C being
_Graph such that A2:
(
C in G .allComponents() &
V = the_Vertices_of C )
;
V in G .componentSet() set v = the
Vertex of
C;
A3:
C is
plain Component of
G
by A2, Th189;
then
the_Vertices_of C c= the_Vertices_of G
by GLIB_000:def 32;
then reconsider v = the
Vertex of
C as
Vertex of
G by TARSKI:def 3;
set C9 = the
plain inducedSubgraph of
G,
(G .reachableFrom v);
A4:
the_Vertices_of the
plain inducedSubgraph of
G,
(G .reachableFrom v) = G .reachableFrom v
by GLIB_000:def 37;
then
the_Vertices_of the
plain inducedSubgraph of
G,
(G .reachableFrom v) = the_Vertices_of C
by A3, GLIB_002:33;
then
C = the
plain inducedSubgraph of
G,
(G .reachableFrom v)
by A3, GLIB_002:32, GLIB_009:44;
hence
V in G .componentSet()
by A2, A4, GLIB_002:def 8;
verum end;
hence
the_Vertices_of (G .allComponents()) = G .componentSet()
by GLIB_014:def 14; verum