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Semi-streaming Algorithms for Submodular Function Maximization Under b-Matching, Matroid, and Matchoid Constraints

  • Chien-Chung Huang,
  • François Sellier

摘要

We consider the problem of maximizing a non-negative submodular function under the b-matching constraint, in the semi-streaming model. When the function is linear, monotone, and non-monotone, we obtain the approximation ratios of \(2+\varepsilon \) 2 + ε , \(3 + 2 \sqrt{2} \approx 5.828\) 3 + 2 2 5.828 , and \(4 + 2 \sqrt{3} \approx 7.464\) 4 + 2 3 7.464 , respectively. We also consider a generalized problem, where a k-uniform hypergraph is given, along with an extra matroid or a \(k'\) k -matchoid constraint imposed on the edges, with the same goal of finding a b-matching that maximizes a submodular function. When the extra constraint is a matroid, we obtain the approximation ratios of \(k + 1 + \varepsilon \) k + 1 + ε , \(k + 2\sqrt{k+1} + 2\) k + 2 k + 1 + 2 , and \(k + 2\sqrt{k + 2} + 3\) k + 2 k + 2 + 3 for linear, monotone and non-monotone submodular functions, respectively. When the extra constraint is a \(k'\) k -matchoid, we attain the approximation ratio \(\frac{8}{3}k+ \frac{64}{9}k' + O(1)\) 8 3 k + 64 9 k + O ( 1 ) for general submodular functions.