theorem :: ALTCAT_1:21

for C being non empty transitive associative AltCatStr
for o1, o2, o3, o4 being Object of C st <^o1,o2^> <> {} & <^o2,o3^> <> {} & <^o3,o4^> <> {} holds
for a being Morphism of o1,o2
for b being Morphism of o2,o3
for c being Morphism of o3,o4 holds c * (b * a) = (c * b) * a