Core Concepts
部分グラフ問題の多項式時間近似スキームを提供する。
Abstract
この記事では、分数木独立数脆弱性に焦点を当て、最大重みの希薄な誘導部分グラフを見つけるメタ問題に対する多項式時間近似スキームを取得します。これは、幾何学的オブジェクトのコレクションに関連する最適化問題がどのように解決されるかを示しています。また、局所的な問題や交差グラフなど異なるグラフクラスに対する既知の多項式時間近似スキームを統一し拡張します。
Stats
G is efficiently fractionally treewidth-fragile if there exists a function f : N → N and an algorithm that, for every k ∈ N and G ∈ G, returns in time poly(|V (G)|) a collection of subsets X1, X2, . . . , Xm ⊆ V (G) such that each vertex of G belongs to at most m/k of the subsets and moreover, for i = 1, . . . , m, the algorithm also returns a tree decomposition of G−Xi of width at most f(k).
Several graph classes are known to be efficiently fractionally treewidth-fragile. In fact, a class G is efficiently fractionally treewidth-fragile in each of the following cases (see, e.g., [45]): G is subgraph-closed and has strongly sublinear separators and bounded maximum degree, G is proper minor-closed, or G consists of intersection graphs of convex objects with bounded aspect ratio in Rd (for fixed d) and the graphs in G have bounded clique number.
Dvořák [39] showed that Independent Set admits a PTAS on every efficiently fractionally treewidth-fragile class.
Quotes
"Given a collection O of geometric objects in Rd, we can consider its intersection graph, the graph whose vertices are the objects in O and where two distinct vertices Oi, Oj ∈ O are adjacent if and only if Oi ∩ Oj ̸= ∅."
"Our main results can be summarized as follows: For each fixed c, h ∈ N and CMSO2 formula ψ, (c, h, ψ)-Max Weight Induced Subgraph admits a PTAS on every efficiently fractionally tree-α-fragile class."
"The main message of our work is that a doubly-relaxed version of a VDT suffices for algorithmic applications and is general enough to hold for several interesting graph classes."