Automorphism Groups and Isometries for Cyclic Orbit Codes
We study orbit codes in the field extension 𝔽_q^n. First we show that the automorphism group of a cyclic orbit code is contained in the normalizer of the Singer subgroup if the orbit is generated by a subspace that is not contained in a proper subfield of 𝔽_q^n. We then generalize to orbits under the normalizer of the Singer subgroup. In that situation some exceptional cases arise and some open cases remain. Finally we characterize linear isometries between such codes.
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