On contracted codes: an extension of Pless' theorem on codes
Tsuyoshi Atsumi · Hokkaido Mathematical Journal · 1996
Using Higman's algebra homomorphism, we prove an extension of Pless' theorem on self-0rthogonal symmetry codes.Let C be a self-0rthogonal code over F , where F is one of GF(2) , GF(3) , GF(4) , or GF(pa) .Let \tau be an automorphism of C .Then, under some additional conditions on \tau , the code can be mapped onto a code of a smaller length that is still self-0rthogonal.