Graphs and Combinatorics ( IF 0.7 ) Pub Date : 2021-06-02 , DOI: 10.1007/s00373-021-02341-6 Dieter Rautenbach , Johannes Redl
For a graph G, two dominating sets D and \(D'\) in G, and a non-negative integer k, the set D is said to k-transform to \(D'\) if there is a sequence \(D_0,\ldots ,D_\ell \) of dominating sets in G such that \(D=D_0\), \(D'=D_\ell \), \(|D_i|\le k\) for every \(i\in \{ 0,1,\ldots ,\ell \}\), and \(D_i\) arises from \(D_{i-1}\) by adding or removing one vertex for every \(i\in \{ 1,\ldots ,\ell \}\). We prove that there is some positive constant c and there are toroidal graphs G of arbitrarily large order n, and two minimum dominating sets D and \(D'\) in G such that D k-transforms to \(D'\) only if \(k\ge \max \{ |D|,|D'|\}+c\sqrt{n}\). Conversely, for every hereditary class \(\mathcal{G}\) that has balanced separators of order \(n\mapsto n^\alpha \) for some \(\alpha <1\), we prove that there is some positive constant C such that, if G is a graph in \(\mathcal{G}\) of order n, and D and \(D'\) are two dominating sets in G, then D k-transforms to \(D'\) for \(k=\max \{ |D|,|D'|\}+\lfloor Cn^\alpha \rfloor \).
中文翻译:
在次要封闭图类中重新配置支配集
对于一个图形G ^,二支配集d和\(d“\)在ģ,和一个非负整数ķ,设定d据说ķ -transform到\(d” \) ,如果有一个序列\( D_0,\ ldots,D_ \ ELL \)在主导套ģ使得\(d = D_0 \) ,\(d“= D_ \ ELL \) ,\(| D_i | \文件ķ\)每\( i \ in \ {0,1, \ ldots, \ell \} \)和\ (D_i \)由\ (D_ {i-1} \)通过为每个\ (i \ in \ {1, \ ldots, \ ell \} \). 我们证明了有一些正的常数Ç和有环形图ģ任意大的顺序的Ñ两个最小支配集,和d和\(d“\)在ģ使得d ķ -transforms到\(d” \)只如果\ (k \ ge \ max \ {| D |, | D '| \} + c \ sqrt {n} \)。相反,对于每个具有平衡顺序分隔符\ (n \ mapto n ^ \ alpha \)对于某些\ (\ alpha <1 \) 的遗传类\ (\ mathcal {G} \),我们证明存在一些正常数C使得,如果G是一个图\ (\ mathcal {G} \)阶n,并且D和\ (D '\)是G中的两个支配集,然后D k 转换为\ (D' \)对于\ (k = \ max \ { | D |, | D'| \} + \ lfloor Cn ^ \ alpha \ rfloor \)。