论文标题
列出了遗传图类中本地溢流的同态
List Locally Surjective Homomorphisms in Hereditary Graph Classes
论文作者
论文摘要
从图$ g $到图$ h $的本地溢出的同态同态是一个边缘保留的映射,从$ v(g)$到$ v(h)$,在每个顶点的附近是$ g $。在列表中,以llshom表示($ h $)表示的本地过滤式同态问题,图$ h $是固定的,实例由图$ g $组成,其每个顶点的每个顶点都配备了$ v(h)$的子集,称为列表。我们要求存在从$ g $到$ h $的本地溢流同态的存在,其中每个顶点$ g $都映射到其列表中的顶点。在本文中,我们研究了$ f $ fule-free Graphs中llshom($ h $)问题的复杂性,即将固定图$ f $作为诱导子绘图的图形。我们的目标是了解哪个对$(h,f)$可以在次指数时间内解决问题。 我们表明,对于所有图表$ h $,对于该问题,该问题在一般图中是NP-HARD,除非$ f $ f $ - f $ f $是有界度的森林或ETH失败,否则在$ f $ fule-free Graph中无法以次指数时间求解。最初的研究表明,可能导致一些易探针结果的有限度森林$ f $的自然亚科是家庭$ \ Mathcal s $由森林组成的$ \ Mathcal s $,其每个组成部分最多都有三片叶子。在这种情况下,我们展示了以下二分法定理:除了可以在一般图中求解多项式时间的情况外,图形$ h \ in \ {p_3,c_4 \} $是唯一允许在$ f $ f $ f $ f $ f pail $ f plafe s $ f plafe s $ f plafe s $ f \ n $ f \ incals s $ f p \ incals s $ f phofe s $ f in c in s $ flafe s $ flafe s $ f in的连接的图。
A locally surjective homomorphism from a graph $G$ to a graph $H$ is an edge-preserving mapping from $V(G)$ to $V(H)$ that is surjective in the neighborhood of each vertex in $G$. In the list locally surjective homomorphism problem, denoted by LLSHom($H$), the graph $H$ is fixed and the instance consists of a graph $G$ whose every vertex is equipped with a subset of $V(H)$, called list. We ask for the existence of a locally surjective homomorphism from $G$ to $H$, where every vertex of $G$ is mapped to a vertex from its list. In this paper, we study the complexity of the LLSHom($H$) problem in $F$-free graphs, i.e., graphs that exclude a fixed graph $F$ as an induced subgraph. We aim to understand for which pairs $(H,F)$ the problem can be solved in subexponential time. We show that for all graphs $H$, for which the problem is NP-hard in general graphs, it cannot be solved in subexponential time in $F$-free graphs unless $F$ is a bounded-degree forest or the ETH fails. The initial study reveals that a natural subfamily of bounded-degree forests $F$ that might lead to some tractability results is the family $\mathcal S$ consisting of forests whose every component has at most three leaves. In this case, we exhibit the following dichotomy theorem: besides the cases that are polynomial-time solvable in general graphs, the graphs $H \in \{P_3,C_4\}$ are the only connected ones that allow for a subexponential-time algorithm in $F$-free graphs for every $F \in \mathcal S$ (unless the ETH fails).