theorem Th43: :: GRAPH_2:43

for G being Graph
for vs1, vs2 being FinSequence of the carrier of G
for c1, c2 being Chain of G st vs1 is_vertex_seq_of c1 & vs2 is_vertex_seq_of c2 & vs1 . (len vs1) = vs2 . 1 holds
c1 ^ c2 is Chain of G