theorem Th58: :: GLIBPRE1:57

for G2 being _Graph
for v, e being object
for w being Vertex of G2
for G1 being addAdjVertex of G2,v,e,w
for v1 being Vertex of G1 st v1 = w & not e in the_Edges_of G2 & not v in the_Vertices_of G2 holds
G1 .reachableFrom v1 = (G2 .reachableFrom w) \/ {v}