Concetti Chiave
The authors present simple and fast combinatorial algorithms for finding maximum weight restricted t-matchings and Kp^q-free t-matchings in graphs with maximum degree at most t+1, where t is an integer greater than 2. The algorithms work for both the weighted and unweighted versions of the problems.
Sintesi
The paper considers the problem of finding a maximum size or weight t-matching without certain forbidden subgraphs in an undirected graph G with maximum degree bounded by t+1, where t is an integer greater than 2.
The authors present algorithms for two variants of this problem:
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The bounded restricted t-matching problem: The goal is to find a maximum weight t-matching that does not contain any Kt+1 or Kt,t subgraphs.
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The bounded Kp^q-free t-matching problem: The goal is to find a maximum weight t-matching that does not contain any Kp^q subgraphs, where t = (p-1)q.
The key ideas behind the algorithms are:
- Constructing an auxiliary multigraph G' by augmenting some of the forbidden subgraphs of G with gadgets containing "half-edges".
- Defining a weight function w' and vectors l, b on G' such that any minimum weight (l, b)-matching in G' corresponds to the complement of the desired restricted or Kp^q-free t-matching in G.
- Carefully handling the cases where the forbidden subgraphs overlap.
The authors show that their algorithms run in O(min{nm log n, n^3}) time for the weighted versions and O(√nm) time for the unweighted versions, which are faster than the previously known algorithms.
Statistiche
The maximum degree of the input graph G is at most t+1.
The weight function w is nonnegative and vertex-induced on every forbidden subgraph.
Citazioni
"We present simple and fast combinatorial algorithms for the weighted and unweighted versions of both the bounded restricted t-matching problem and the bounded Kp^q-free t-matching problem, both for t ≥ 3."
"The presented algorithms are the first ones for the weighted versions of these problems, and for the unweighted ones, are faster than those known previously."