Submodular maximization is one of the central topics in combinatorial optimization. It has found numerous applications in the real world. In the past decades, a series of algorithms have been proposed for this problem. However, most of the state-of-the-art algorithms are randomized. There remain non-negligible gaps with respect to approximation ratios between deterministic and randomized algorithms in submodular maximization. In this paper, we propose deterministic algorithms with improved approximation ratios for non-monotone submodular maximization. Specifically, for the matroid constraint, we provide a deterministic $0.283-o(1)$ approximation algorithm, while the previous best deterministic algorithm only achieves a $1/4$ approximation ratio. For the knapsack constraint, we provide a deterministic $1/4$ approximation algorithm, while the previous best deterministic algorithm only achieves a $1/6$ approximation ratio. For the linear packing constraints with large widths, we provide a deterministic $1/6-\epsilon$ approximation algorithm. To the best of our knowledge, there is currently no deterministic approximation algorithm for the constraints.
翻译:子模型最大化问题是组合优化中的一个中心话题。它已经在实际应用中找到了许多应用。在过去的几十年中,已经提出了许多算法来解决这个问题。然而,大多数最先进的算法都是随机的。在子模型最大化中,确定性算法和随机化算法之间的近似度存在非常大的差距。在本文中,我们针对非单调子模型最大化问题提出了改进的确定性算法,达到了更好的近似精度。具体来说,对于拟阵约束,我们提供了一个确定性的$0.283-o(1)$近似算法,而以前最好的确定性算法只能达到$1/4$的近似度。对于背包约束,我们提供了一个确定性的$1/4$近似算法,而以前最好的确定性算法只能达到$1/6$的近似度。对于具有较大宽度的线性填充约束,我们提供一个确定性的$1/6-\epsilon$近似算法。据我们所知,目前还没有确定性逼近算法可以解决这些约束条件。