5 research outputs found
Binary linear codes with a fixed point free permutation automorphism of order three
We investigate the structural properties of binary linear codes whose
permutation automorphism group has a fixed point free automorphism of order
. We prove that up to dimension or codimension , there is no binary
linear code whose permutation automorphism group is generated by a fixed point
free permutation of order . We also prove that there is no binary
-dimensional linear code whose length is at least and whose permutation
automorphism group is generated by a fixed point free permutation of order .Comment: 10 page
On the Structure of the Linear Codes with a Given Automorphism
The purpose of this paper is to present the structure of the linear codes
over a finite field with q elements that have a permutation automorphism of
order m. These codes can be considered as generalized quasi-cyclic codes.
Quasi-cyclic codes and almost quasi-cyclic codes are discussed in detail,
presenting necessary and sufficient conditions for which linear codes with such
an automorphism are self-orthogonal, self-dual, or linear complementary dual
Self-Dual Codes
Self-dual codes are important because many of the best codes known are of
this type and they have a rich mathematical theory. Topics covered in this
survey include codes over F_2, F_3, F_4, F_q, Z_4, Z_m, shadow codes, weight
enumerators, Gleason-Pierce theorem, invariant theory, Gleason theorems,
bounds, mass formulae, enumeration, extremal codes, open problems. There is a
comprehensive bibliography.Comment: 136 page
C贸digos q-arios autoduales con un automorfismos de orden primo
En la teor铆a cl谩sica de c贸digos, los c贸digos autoduales juegan un papel muy importante por su rica estructura algebraica. Para ellos la distancia m铆nima esta acotada superiormente y se denominan extremales aquellos c贸digos que alcanzan dicha cota. Estos son particularmente interesantes, ya que ellos pueden corregir el mayor numero de errores entre todos los c贸digos autoduales. El prop贸sito de este trabajo es analizar la estructura algebraica de un c贸digo autodual q-ario con un automorfismo de orden primo distinto a la caracter铆stica del cuerpo y posteriormente con ello, dar una clasificaci贸n de todos los c贸digos extremales Tipo I y Tipo III de longitud 60 con un automorfismo de orden 29. Para esto hacemos uso de la descomposici贸n del c贸digo C como la suma directa de dos subc贸digos e implementamos herramientas computacionales sobre todas las posibles matrices del c贸digo. Concretamente, demostramos que existen exactamente tres [60, 30, 12] c贸digos extremales Tipo I y existen tres c贸digos extremales [60, 30, 18] Tipo III, con un automorfismo de orden 29. como la suma directa de dos subc贸digos e implementamos herramientas computacionales sobre todas las posibles matrices del c贸digo. Concretamente, demostramos que existen exactamente tres [60, 30, 12] c贸digos extremales Tipo I y tres c贸digos extremales [60, 30, 18] Tipo III, con un automorfismo de orden 29.Maestr铆aMagister en Matem谩tica