论文标题
在线Mincut:竞争和遗憾分析
Online MinCut: Competitive and Regret Analysis
论文作者
论文摘要
在本文中,我们研究了在线环境中的微小问题。我们考虑了两个不同的模型:a)竞争性分析和b)遗憾分析。在竞争环境中,我们考虑顶点到达模型;每当新的顶点到达时,就会揭示有关已知顶点的邻居。在线算法必须做出不可撤销的决定,以确定顶点所属于的切割的侧面,以最大程度地减少最终切割的大小。考虑了各种模型。 1)对于经典和咨询模型,我们就确定性算法的竞争比率紧密界定。 2)接下来,我们考虑很少的半反向输入:随机到达的随机顺序,具有对抗性生成和稀疏图。 3)最后,我们在贪婪策略方面得出了\ mc-type问题的某些结构特性。 最后,我们考虑了具有各种预算$ v_t $的非平稳遗憾设置,并为遗憾功能提供紧身的界限。具体来说,我们表明,如果$ v_t $是$ t $(回合数)中的sublinear,那么有一种确定性算法实现了sublinear遗憾($ o(v_t)$)。此外,即使允许随机化,这也是最佳的。
In this paper we study the mincut problem in the online setting. We consider two distinct models: A) competitive analysis and B) regret analysis. In the competitive setting we consider the vertex arrival model; whenever a new vertex arrives it's neighborhood with respect to the set of known vertices is revealed. An online algorithm must make an irrevocable decision to determine the side of the cut that the vertex must belong to in order to minimize the size of the final cut. Various models are considered. 1) For classical and advice models we give tight bounds on the competitive ratio of deterministic algorithms. 2) Next we consider few semi-adversarial inputs: random order of arrival with adversarially generated and sparse graphs. 3) Lastly we derive some structural properties of \mc-type problems with respect to greedy strategies. Finally we consider a non-stationary regret setting with a variational budget $V_T$ and give tights bounds on the regret function. Specifically, we show that if $V_T$ is sublinear in $T$ (number of rounds) then there is a deterministic algorithm achieving a sublinear regret bound ($O(V_T)$). Further, this is optimal, even if randomization is allowed.