:: deftheorem Def14 defines directed GLIB_010:def 14 :
for G1, G2 being _Graph
for F being PGraphMapping of G1,G2 holds
( F is directed iff for e, v, w being object st e in dom (F _E) & v in dom (F _V) & w in dom (F _V) & e DJoins v,w,G1 holds
(F _E) . e DJoins (F _V) . v,(F _V) . w,G2 );