On the Equivalence of Some Generalized Concatenated Codes and Extended Cyclic Codes

It is known that cyclic codes of composite length are equivalent to generalized concatenated codes with inner cyclic codes and outer cyclic or constacyclic codes. Here it is shown that there is a large class of extended cyclic codes of length Q/sup m/, that can be constructed by generalized concatenation of shorter extended cyclic codes. This class includes the generalized Reed-Muller codes and the Eucliclean geometry codes. In many cases a simple multistage decoder corrects all errors of weight less than half of the true minimum distance of the code.