Self-Dual Codes over ${\text{GF}}( 3 )$

This paper studies self-dual and maximal self-orthogonal codes over ${\text{GF}}( 3 )$. First, a number of Gleason-type theorems are given, describing the weight enumerators of such codes. Second, a table of all such codes of length $\leqq 12$ is constructed. Finally, the complete weight enumerators of various quadratic residue and symmetry codes of length $\leqq 60$ are obtained.