theorem Th13: :: ALTCAT_2:13

for C being Category
for i, j, k being Object of C st Hom (i,j) <> {} & Hom (j,k) <> {} holds
for f being Morphism of i,j
for g being Morphism of j,k holds ((the_comps_of C) . (i,j,k)) . (g,f) = g * f