Mixed Hamming packings are considered: the maximal cardinality given a minimum codeword Hamming distance of mixed codes is addressed via mixed integer programming models. Adopting the concept of contact graph from classical continuous sphere packing problems, a reduction technique for the models is introduced, which enables their efficient solution. Several best known upper bounds are improved and some of them are found to be sharp.

翻译：考虑混合汉明堆积问题：通过混合整数规划模型，研究在最小码字汉明距离约束下混合码的最大基数。借鉴经典连续球堆积问题中接触图的概念，引入模型简化技术，从而实现对模型的高效求解。多个已知最佳上界得到改进，其中部分被证明是紧致的。