منابع مشابه
On extremal self-dual codes of length 120
We prove that the only primes which may divide the order of the automorphism group of a putative binary self-dual doubly-even [120, 60, 24] code are 2, 3, 5, 7, 19, 23 and 29. Furthermore we prove that automorphisms of prime order p ≥ 5 have a unique cycle structure.
متن کاملNew extremal self-dual codes of length 62 and related extremal self-dual codes
In this correspondence, new extremal self-dual codes of length 62 are constructed with weight enumerators of three different types. Two of these types were not represented by any known code up till now. All these codes possess an automorphism of order 15. Some of them are used to construct extremal self-dual codes of length 60 by the method of subtracting. Manuscript received November 20, 2001;...
متن کاملOn extremal self-dual ternary codes of length 48
The notion of an extremal self-dual code has been introduced in 1 . As Gleason 2 remarks onemay use invariance properties of the weight enumerator of a self-dual code to deduce upper bounds on the minimum distance. Extremal codes are self-dual codes that achieve these bounds. The most wanted extremal code is a binary self-dual doubly even code of length 72 and minimum distance 16. One frequentl...
متن کاملExtremal self-dual codes
In the present thesis we consider extremal self-dual codes. We mainly concentrate on Type II codes (binary doubly-even codes), which may theoretically exist for lengths n = 8k ≤ 3928. It is noteworthy that extremal Type II codes have been actually constructed only for 13 lengths, 136 being the largest. Over the last decades the study of extremal codes became inseparable from the study of their ...
متن کاملClassification of ternary extremal self-dual codes of length 28
All 28-dimensional unimodular lattices with minimum norm 3 are known. Using this classification, we give a classification of ternary extremal self-dual codes of length 28. Up to equivalence, there are 6,931 such codes.
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ژورنال
عنوان ژورنال: Designs, Codes and Cryptography
سال: 2013
ISSN: 0925-1022,1573-7586
DOI: 10.1007/s10623-013-9902-8