Long cyclic codes are good

Long quasi-cyclic codes of any fixed index > 1 have been shown to be asymptotically good, depending on Artin primitive root conjecture in (A. Alahmadi, C. Güneri, H. Shoaib, P. Solé, 2017). We use this recent result to construct good long additive cyclic codes on any extension of fixed degree of the base field. Similarly selfdual double circulant codes, and self-dual four circulant codes, have been shown to be good, also depending on Artin primitive root conjecture in (A. Alahmadi, F. Özdemir, P. Solé, 2017) and ( M. Shi, H. Zhu, P. Solé, 2017) respectively. Building on these recent results, we can show that long cyclic codes are good over Fq, for many classes of q’s. This is a partial solution to a fifty year old open problem.