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arXiv 1808.06320cs.GT
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严格凸空间中设施选址的群策略保护机制的刻画

Characterization of Group-Strategyproof Mechanisms for Facility Location in Strictly Convex Space

Pingzhong Tang, Dingli Yu, Shengyu Zhao

摘要:

在任意无约束严格凸空间中,刻画了单设施选址博弈的群体防策略机制类。一种机制是\emph{group-strategyproof},如果没有一组代理人可以误报,使其所有成员都更好地\emph{strictly}。严格凸空间是赋范向量空间,其中$\|x+y\|<2$对任何一对不同的单位向量$x \neq y$成立,例如,任何带有$p\in (1,\infty)$的$L_p$空间。我们表明,任何确定性的,一致的,组strategyproof机制必须是独裁的,和任何随机的,一致的,防御不变的,组strategyproof机制必须是\emph{2-dictatorial}。这里,如果随机机制的彩票输出必须分布在两个独裁者输入之间的线段上,则该机制是2-独裁的。如果一个机构的输出遵循输入的相同平移,则该机构是平移不变的。我们的特征直接意味着,任何(随机)的预防不变近似算法满足组strategyprofness属性有一个下界的$2$近似的最大成本(每当$n \geq 3$),和$n/2 - 1$的社会成本。我们还发现了一个算法,$2$ -近似的最大成本和$n/2$ -近似的社会成本,证明边界是(几乎)紧。

英文摘要:

We characterize the class of group-strategyproof mechanisms for the single facility location game in any unconstrained strictly convex space. A mechanism is \emph{group-strategyproof}, if no group of agents can misreport so that all its members are \emph{strictly} better off. A strictly convex space is a normed vector space where $\|x+y\|<2$ holds for any pair of different unit vectors $x \neq y$, e.g., any $L_p$ space with $p\in (1,\infty)$. We show that any deterministic, unanimous, group-strategyproof mechanism must be dictatorial, and that any randomized, unanimous, translation-invariant, group-strategyproof mechanism must be \emph{2-dictatorial}. Here a randomized mechanism is 2-dictatorial if the lottery output of the mechanism must be distributed on the line segment between two dictators' inputs. A mechanism is translation-invariant if the output of the mechanism follows the same translation of the input. Our characterization directly implies that any (randomized) translation-invariant approximation algorithm satisfying the group-strategyproofness property has a lower bound of $2$-approximation for maximum cost (whenever $n \geq 3$), and $n/2 - 1$ for social cost. We also find an algorithm that $2$-approximates the maximum cost and $n/2$-approximates the social cost, proving the bounds to be (almost) tight.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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