GRAY IMAGES OF A CLASS OF NEGACYCLIC CODES OVER GR(4,2)
环GR(4,2)上一类负循环码的Gray象

This paper investigates the Gray images of negacyclic codes of length $2^{s}$ over $GR(4,2)$. It is proved that the Gray image of a negacyclic code of length $2^{s}$ over $GR(4,2)$ is a distance-invariant linear quasicyclic code of index 2 and length $2^{s+2}$ over $F_{4}$. The homogeneous distances of negacyclic codes of length $2^{s}$ over $GR(2^{a},m)$ in general are calculated. The homogeneous distances are used to determine the Hamming distances of the Gray images of negacyclic codes of length $2^{s}$ over $GR(4,2)$.