In this work, Gray images of formally self-dual codes over the ring S₄ = F₂[u]/‹u⁴› and some of their construction methods are considered. As a result, a considerable number of good formally self-dual binary codes with large automorphism groups have been obtained from the Gray images of formally self-dual codes over S₄. Some have better minimum distances than the best known binary self-dual codes of the same lengths.Publisher's Versio
