V. Levenshtein first proposed the sequence reconstruction problem in 2001. This problem studies the model where the same sequence from some set is transmitted over multiple channels, and the decoder receives the different outputs. Assume that the transmitted sequence is at distance $d$ from some code and there are at most $r$ errors in every channel. Then the sequence reconstruction problem is to find the minimum number of channels required to recover exactly the transmitted sequence that has to be greater than the maximum intersection between two metric balls of radius $r$, where the distance between their centers is at least $d$. In this paper, we study the sequence reconstruction problem of permutations under the Hamming distance. In this model, we define a Cayley graph and find the exact value of the largest intersection of two metric balls in this graph under the Hamming distance for $r=4$ with $d\geqslant 5$, and for $d=2r$.
翻译:Levenshtein首先提出2001年的序列重建问题。 这个问题研究的是某些数据集的同一序列通过多个频道传送的模型, 解码器得到不同的输出。 假设传输的序列距离某些代码为$d, 每个频道的错误最多为$r。 然后, 序列重建的问题是找到准确恢复两个半径方圆1美元的最大交叉点所需的最起码的频道数量, 这个半径1美元, 其中心之间的距离至少是$d。 在本文中, 我们研究了Hamming 距离下变形的序列重建问题。 在这个模型中, 我们定义了一个 Cayley 图表, 并找到在Hamming 距离下最大交叉点的两个公球的准确价值, 以美元=4美元, 以美元计为5美元, 以美元=2美元。