Self-dual codes and quadratic residue codes over the ring ${\mathbb{Z}}_9+u{\mathbb{Z}}_9$

Jian Gao, XianFang Wang, Fang-Wei Fu

In this paper, we introduce a new definitions of the Gray weight and the Gray map for linear codes over ${\mathbb{Z}}_9+u{\mathbb{Z}}_9$ with $u^2=u$. Some results on self-dual codes o…