🤖 AI Summary
This paper investigates the Partial Generalized Dominating Set problem on graphs of bounded treewidth: given a graph $G$ and integers $k,ell$, determine whether there exists a vertex set $S$ of size at most $k$ such that at most $ell$ vertices violate the $(sigma,
ho)$-domination condition. Using tree decompositions and dynamic programming, we design a tight algorithm running in $(s_sigma^p + s_
ho^p + 2)^{mathrm{tw}} cdot |G|^{O(1)}$ time, where $s_sigma^p$ and $s_
ho^p$ are structural parameters intrinsic to the domination constraints $sigma$ and $
ho$. We establish matching algorithmic and complexity lower bounds: via a fine-grained reduction from SETH under Primal Pathwidth, we prove that the base $s_sigma^p + s_
ho^p + 2$ in the exponent is asymptotically optimal. This yields the first complete characterization of the precise time complexity boundary for this problem class, revealing that its computational hardness is fundamentally governed by $s_sigma^p$ and $s_
ho^p$.
📝 Abstract
The $(sigma,
ho)$-domination framework introduced by Telle [Nord. J. Comput.'94] captures many classical graph problems. For fixed sets $sigma,
ho$ of non-negative integers, a $(sigma,
ho)$-set of a graph $G$ is a set $S$ such that for every $vin V(G)$, we have (1) if $v in S$, then $|N(v) cap S| in sigma$, and (2) if $v
otin S$, then $|N(v) cap S| in
ho$. We initiate the study of a natural partial variant of the problem, in which the constraints given by $sigma,
ho$ need not be fulfilled for all vertices, but we want to maximize the number of vertices that are happy in the sense that they satisfy (1) or (2) above. Given a graph $G$ and integers $k$ and $ell$, the task of $(sigma,
ho)$-MinParDomSet is to decide whether there is a set $S subseteq V(G)$ of size at most $k$ such that at most $ell$ vertices of the graph are not happy under $S$. We consider the problem on graphs of bounded treewidth for nonempty finite or simple cofinite sets $sigma$ and $
ho$, and give matching upper and lower bounds for every such fixed $sigma$ and $
ho$ (under the Primal Pathwidth Strong Exponential Time Hypothesis). Let $s_sigma^ extsf{p} = max sigma + 1$ when $sigma$ is finite, and $min sigma$ when $sigma$ is simple cofinite; define $s_
ho^{ extsf{p}}$ similarly for $
ho$. We show that the problem $(sigma,
ho)$-MinParDomSet (1) can be solved in time $(s_sigma^ extsf{p} + s_
ho^{ extsf{p}} + 2)^{tw} cdot |G|^{O(1)}$, when a tree decomposition of width $tw$ is provided together with the input, and (2) for any $varepsilon>0$, no algorithm can exist that solves the problem in time $(s_sigma^ extsf{p} + s_
ho^{ extsf{p}} + 2 - varepsilon)^{pw} cdot |G|^{O(1)}$, even when a path decomposition of width $pw$ is provided together with the input.