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arXiv · 0902.3883

Directed Graph Representation of Half-Rate Additive Codes over GF(4)

Lars Eirik Danielsen·Matthew G. Parker
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Abstract

We show that (n,2^n) additive codes over GF(4) can be represented as directed graphs. This generalizes earlier results on self-dual additive codes over GF(4), which correspond to undirected graphs. Graph representation reduces the complexity of code classification, and enables us to classify additive (n,2^n) codes over GF(4) of length up to 7. From this we also derive classifications of isodual and formally self-dual codes. We introduce new constructions of circulant and bordered circulant directed graph codes, and show that these codes will always be isodual. A computer search of all such codes of length up to 26 reveals that these constructions produce many codes of high minimum distance. In particular, we find new near-extremal formally self-dual codes of length 11 and 13, and isodual codes of length 24, 25, and 26 with better minimum distance than the best known self-dual codes.

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BibTeXRIS

Lars Eirik Danielsen, Matthew G. Parker. 2009-02-23. Directed Graph Representation of Half-Rate Additive Codes over GF(4). https://doi.org/10.1007/s10623-010-9469-6

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