For a class $\mathcal{G}$ of graphs, the objective of \textsc{Subgraph Complementation to} $\mathcal{G}$ is to find whether there exists a subset $S$ of vertices of the input graph $G$ such that modifying $G$ by complementing the subgraph induced by $S$ results in a graph in $\mathcal{G}$. We obtain a polynomial-time algorithm for the problem when $\mathcal{G}$ is the class of graphs with minimum degree at least $k$, for a constant $k$, answering an open problem by Fomin et al. (Algorithmica, 2020). When $\mathcal{G}$ is the class of graphs without any induced copies of the star graph on $t+1$ vertices (for any constant $t\geq 3$) and diamond, we obtain a polynomial-time algorithm for the problem. This is in contrast with a result by Antony et al. (Algorithmica, 2022) that the problem is NP-complete and cannot be solved in subexponential-time (assuming the Exponential Time Hypothesis) when $\mathcal{G}$ is the class of graphs without any induced copies of the star graph on $t+1$ vertices, for every constant $t\geq 5$.
翻译:对于图类$\mathcal{G}$,\textsc{子图补全到}$\mathcal{G}$问题的目标是:判断输入图$G$的顶点集是否存在子集$S$,使得通过对$S$诱导的子图进行补全操作修改$G$后,所得图属于$\mathcal{G}$。当$\mathcal{G}$为最小度数至少为$k$($k$为常数)的图类时,我们得到了该问题的多项式时间算法,解决了Fomin等人(Algorithmica, 2020)提出的一个开放问题。当$\mathcal{G}$为不含任何$t+1$个顶点星图(对任意常数$t\geq 3$)和钻石图作为诱导子图的图类时,我们同样获得了该问题的多项式时间算法。这与Antony等人(Algorithmica, 2022)的结果形成对比:后者表明,对于每个常数$t\geq 5$,当$\mathcal{G}$为不含任何$t+1$个顶点星图作为诱导子图的图类时,该问题是NP完全的,且无法在次指数时间内求解(假设指数时间假说成立)。