Extended maximal self-orthogonal codes

Self-dual and maximal self-orthogonal codes over GF(q), where q is even or q 1(mod 4), are extensively studied in this paper. We prove that every maximal self-orthogonal code can be extended to a self-dual code as in the case of binary Golay code. Using these results, we show that a self-dual code can also be constructed by gluing theory even if the sum of the lengths of the gluing components is odd. Furthermore, the (Hamming) weight enumerator W-(C) over bar(x, y) of a self-dual code (C) over bar is given in terms of a maximal self-orthogonal code C, where (C) over bar is obtained by the extension of C.