theorem Th15: :: MSSCYC_1:16

for G being non void Graph
for c, c1, c2 being non empty directed Chain of G st c = c1 ^ c2 holds
( (vertex-seq c) . 1 = (vertex-seq c1) . 1 & (vertex-seq c) . ((len c) + 1) = (vertex-seq c2) . ((len c2) + 1) )