Constructing covering codes with given automorphisms
Let K(n, r) denote the minimum cardinality of a binary covering code of length n and covering radius r. Constructions of covering codes give upper bounds on K(n, r). It is here shown how computer searches for covering codes can be sped up by requiring that the code has a given (not necessarily full) automorphism group. Tabu search is used to find orbits of words that lead to a covering. In particular, a code D is found which proves K(13, 1) less than or equal to 704 a new record. A direct construction of D is given, and its full automorphism group is shown to be the general linear group GL(3, 3). It is proved that D is a perfect dominating set (each word not in D is covered by exactly one word in D) and is a counterexample to the recent Uniformity Conjecture of Weichsel.
covering code automorphism group tabu search dominating set hypercube