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In this paper, we study cyclic self-orthogonal codes over Z 2 m for any odd length. We give the generator polynomials of cyclic self-orthogonal codes over Z 2 m . By using these generator polynomials, we obtain a sufficient and necessary condition for the existence of nontrivial cyclic self-orthogonal codes over Z 2 m and determine the number of such codes for a given odd length. Some results about cyclic self-dual codes over Z 2 m are included. [ABSTRACT FROM AUTHOR]

Abstract We investigate the minimum distance of q -ary negacyclic codes of length q m − 1 2 generated by a product of two distinct minimal polynomials. A necessary and sufficient condition on the minimum distance of such negacyclic codes is given. Several classes of optimal quinary negacyclic codes with parameters [ (5 m − 1) / 2 , (5 m − 1) / 2 − 2 m , 4 ] are constructed. The dual codes of a subclass of the quinary negacyclic codes are studied. A comparison with cyclic codes is also presented. [ABSTRACT FROM AUTHOR]

Let p ≠ 3 be any prime and l ≠ 3 be any odd prime with gcd ⁡ ( p , l ) = 1 . The multiplicative group F q ⁎ = 〈 ξ 〉 can be decomposed into mutually disjoint union of gcd ⁡ ( q − 1 , 3 l p s ) cosets over the subgroup 〈 ξ 3 l p s 〉 , where ξ is a primitive ( q − 1 ) th root of unity. We classify all repeated-root constacyclic codes of length 3 l p s over the finite field F q into some equivalence classes by this decomposition, where q = p m , s and m are positive integers. According to these equivalence classes, we explicitly determine the generator polynomials of all repeated-root constacyclic codes of length 3 l p s over F q and their dual codes. Self-dual cyclic codes of length 3 l p s over F q exist only when p = 2 . We give all self-dual cyclic codes of length 3 ⋅ 2 s l over F 2 m and their enumeration. We also determine the minimum Hamming distance of these codes when gcd ⁡ ( 3 , q − 1 ) = 1 and l = 1 . [ABSTRACT FROM AUTHOR]