let G1, G2 be _Graph; for F being directed PGraphMapping of G1,G2 st F _V is one-to-one holds
F is semi-Dcontinuous
let F be directed PGraphMapping of G1,G2; ( F _V is one-to-one implies F is semi-Dcontinuous )
assume A1:
F _V is one-to-one
; F is semi-Dcontinuous
let e, v, w be object ; GLIB_010:def 17 ( e in dom (F _E) & v in dom (F _V) & w in dom (F _V) & (F _E) . e DJoins (F _V) . v,(F _V) . w,G2 implies e DJoins v,w,G1 )
assume that
A2:
( e in dom (F _E) & v in dom (F _V) & w in dom (F _V) )
and
A3:
(F _E) . e DJoins (F _V) . v,(F _V) . w,G2
; e DJoins v,w,G1
set v1 = (the_Source_of G1) . e;
set v2 = (the_Target_of G1) . e;
A4:
e DJoins (the_Source_of G1) . e,(the_Target_of G1) . e,G1
by A2, GLIB_000:def 14;
A5:
( (the_Source_of G1) . e in dom (F _V) & (the_Target_of G1) . e in dom (F _V) )
by A2, Th5;
then
(F _E) . e DJoins (F _V) . ((the_Source_of G1) . e),(F _V) . ((the_Target_of G1) . e),G2
by A2, A4, Def14;
then
( (F _V) . ((the_Source_of G1) . e) = (F _V) . v & (F _V) . ((the_Target_of G1) . e) = (F _V) . w )
by A3, GLIB_000:125;
then
( (the_Source_of G1) . e = v & (the_Target_of G1) . e = w )
by A1, A2, A5, FUNCT_1:def 4;
hence
e DJoins v,w,G1
by A4; verum