theorem Th113: :: GLENUM00:113

for G1, G2 being _Graph
for F being PGraphMapping of G1,G2 st F is weak_SG-embedding & rng (F _V) = the_Vertices_of G2 holds
rng ((SG2SGFunc F) | (G1 .allSpanningForests())) c= G2 .allSpanningForests()