Recent work in iterative voting has defined the difference in social welfare between the truthful winner and worst-case equilibrium winner, due to repeated strategic manipulations, known as the additive dynamic price of anarchy (ADPoA). While all iterative plurality winners have been shown to differ from truth by at most one initial vote, it is less understood how agents' welfare changes in equilibrium. To this end, we differentiate agents' utility from their iteration mechanism and determine iterative plurality's ADPoA in the worst- and average-case. We first negatively demonstrate that the worst-case ADPoA is linear in the number of agents. In expectation, rather, equilibrium winners have a constant order welfare advantage over the truthful winner. Our positive results illustrate the prospect for social welfare to increase due to strategic manipulation.
翻译:最近迭代投票工作确定了真实赢家与最坏情况均衡赢家在社会福利方面的差别,原因是多次战略操纵,即所谓的无政府状态的累加动态价格(ADPOA ) 。 虽然所有迭代多元赢家在最初的投票中显示与事实不同,但人们不太了解代理人在平衡方面的福利变化。为此,我们区分代理人与其迭代机制的效用,并在最坏和平均的情况下确定迭代多元化的ADPA。我们首先消极地证明,最坏的ADPOA在代理人数量上是线性的。相反,预期平衡赢家对诚实赢家有固定的顺序福利优势。我们的积极结果显示了社会福利因战略操纵而增加的前景。