Type IV self-dual codes over rings
In this paper, we study Type IV self-dual codes over the commutative rings of order 4. Gleason-type theorems of Type IV codes and their shadow codes are investigated. A mass formula of Type IV codes over these rings are given. We give a classification of Type IV codes over Z(4) and F-2 + uF(2) for reasonable lengths. We also construct a number of optimal type IV codes.
self-dual codes codes over rings divisible codes lattices