Self-dual Z4-codes and Hadamard matrices
Discrete Mathematics
Self-dual Codes-Theme and Variations
AAECC-14 Proceedings of the 14th International Symposium on Applied Algebra, Algebraic Algorithms and Error-Correcting Codes
Construction of new extremal self-dual codes
Discrete Mathematics
Extremal weight enumerators and ultraspherical polynomials
Discrete Mathematics
New Extremal Type I Codes of Lengths 40, 42, and 44
Designs, Codes and Cryptography
Designs and self-dual codes with long shadows
Journal of Combinatorial Theory Series A
On some self-dual codes and unimodular lattices in dimension 48
European Journal of Combinatorics
Extremal self-dual codes of length 64 through neighbors and covering radii
Designs, Codes and Cryptography
Nonexistence of near-extremal formally self-dual even codes of length divisible by 8
Discrete Applied Mathematics
Binary self-dual codes with automorphisms of order 23
Designs, Codes and Cryptography
The nonexistence of near-extremal formally self-dual codes
Designs, Codes and Cryptography
Formally self-dual additive codes over F4
Journal of Symbolic Computation
New binary singly even self-dual codes
IEEE Transactions on Information Theory
Automorphisms of extremal self-dual codes
IEEE Transactions on Information Theory
The binary extremal self-dual codes of lengths 38 and 40
Designs, Codes and Cryptography
A note on formally self-dual even codes of length divisible by 8
Finite Fields and Their Applications
A mass formula for self-dual permutation codes
Finite Fields and Their Applications
Determination of weight enumerators of binary extremal self-dual [42,21,8] codes
Finite Fields and Their Applications
Extremal self-dual [40,20,8] codes with covering radius 7
Finite Fields and Their Applications
New extremal self-dual doubly-even binary codes of length 88
Finite Fields and Their Applications
On the classification and enumeration of self-dual codes
Finite Fields and Their Applications
Finite Fields and Their Applications
New optimal [52, 26, 10] self-dual codes
Designs, Codes and Cryptography
| Hi-index | 754.96 |
Conway and Sloane (1990) have previously given an upper bound on the minimum distance of a singly-even self-dual binary code, using the concept of the shadow of a self-dual code. We improve their bound, finding that the minimum distance of a self-dual binary code of length n is at most 4[n/24]+4, except when n mod 24=22, when the bound is 4[n/24]+6. We also show that a code of length a multiple of 24 meeting the bound cannot be singly-even. The same technique gives similar results for additive codes over GF(4) (relevant to quantum coding theory)