Abstract | ||
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We study the concept of emph{compactor}, which may be seen as a counting-analogue of kernelization in counting parameterized complexity. For a function $F:Sigma^*to Bbb{N}$ and a parameterization $kappa: Sigma^*to Bbb{N}$, a compactor $({sf P},{sf M})$ consists of a polynomial-time computable function ${sf P}$, called emph{condenser}, and a computable function ${sf M}$, called emph{extractor}, such that $F={sf M}circ {sf P}$, and the condensing ${sf P}(x)$ of $x$ has length at most $s(kappa(x))$, for any input $xin Sigma^*.$ If $s$ is a polynomial function, then the compactor is said to be of polynomial-size. Although the study on counting-analogue of kernelization is not unprecedented, it has received little attention so far. We study a family of vertex-certified counting problems on graphs that are MSOL-expressible; that is, for an MSOL-formula $phi$ with one free set variable to be interpreted as a vertex subset, we want to count all $Asubseteq V(G)$ where $|A|=k$ and $(G,A)models phi.$ In this paper, we prove that every vertex-certified counting problems on graphs that is emph{MSOL-expressible} and emph{treewidth modulable}, when parameterized by $k$, admits a polynomial-size compactor on $H$-topological-minor-free graphs with condensing time $O(k^2n^2)$ and decoding time $2^{O(k)}.$ This implies the existence of an {sf FPT}-algorithm of running time $O(n^2k^2)+2^{O(k)}.$ All aforementioned complexities are under the Uniform Cost Measure (UCM) model where numbers can be stored in constant space and arithmetic operations can be done in constant time. |
Year | DOI | Venue |
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2018 | 10.4230/LIPIcs.ISAAC.2018.20 | ISAAC |
DocType | Volume | Citations |
Conference | abs/1809.08160 | 0 |
PageRank | References | Authors |
0.34 | 0 | 3 |
Name | Order | Citations | PageRank |
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Eun Jung Kim | 1 | 873 | 67.64 |
Maria J. Serna | 2 | 473 | 70.53 |
Dimitrios M. Thilikos | 3 | 1844 | 124.72 |