New identities relating wild Goppa codes
New identities relating wild Goppa codes
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与野生 Goppa 代码相关的新身份
DOI:
10.1016/j.ffa.2014.04.007
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发表时间:
2013
期刊:
影响因子:
--
通讯作者:
J. Tillich
中科院分区:
文献类型:
--
作者:
Alain Couvreur;A. Otmani;J. Tillich
For a given support L∈ F q m n and a polynomial g∈ F q m [x] with no roots in F q m, we prove equality between the q-ary Goppa codes Γ q (L, N (g))= Γ q (L, N (g)/g) where N (g) denotes the norm of g, that is g q m− 1+⋯+ q+ 1. In particular, for m= 2, that is, for a quadratic extension, we get Γ q (L, g q)= Γ q (L, g q+ 1). If g has roots in F q m, then we do not necessarily have equality and we prove that the difference of the dimensions of the two codes is bounded above by the number of distinct roots of g in F q m. These identities provide numerous code equivalences and improved designed parameters for some families of classical Goppa codes.