Improved linear programming bound on sizes of doubly constant-weight codes

摘要

In this paper we give new constraints on the distance distribution of doubly constant-weight (binary) codes. These constraints improve the linear programming bound on sizes of doubly constant-weight codes. Computations are done for all codes of length n = 28 and all improved upper bounds are shown. We moreover show that the improved upper bounds give rise to further new upper bounds. (C) 2018 Elsevier Inc. All rights reserved.