We analyse a coalition formation game between strategic service providers of a congestible service. The key novelty of our formulation is that it is a constant sum game, i.e., the total payoff across all service providers (or coalitions of providers) is fixed, and dictated by the size of the market. The game thus captures the tension between resource pooling (to benefit from the resulting statistical economies of scale) and competition between coalitions over market share. In a departure from the prior literature on resource pooling for congestible services, we show that the grand coalition is in general not stable, once we allow for competition over market share. In fact, under classical notions of stability (defined via blocking by any coalition), we show that no partition is stable. This motivates us to introduce more restricted (and relevant) notions of blocking; interestingly, we find that the stable configurations under these novel notions of stability are duopolies, where the dominant coalition exploits its economies of scale to corner a disproportionate market share. Furthermore, we completely characterise the stable duopolies in heavy and light traffic regimes.

翻译：我们分析了战略服务提供商在拥塞服务中的联盟形成博弈。我们模型的关键创新在于它是一个常和博弈，即所有服务提供商（或提供商联盟）的总收益是固定的，并由市场规模决定。因此，该博弈捕捉了资源池化（以利用由此产生的统计规模经济）与联盟之间对市场份额的竞争之间的张力。与以往关于拥塞服务资源池化的文献不同，我们发现在允许对市场份额进行竞争后，大联盟通常不稳定。实际上，在经典的稳定性概念（由任何联盟通过阻止来定义）下，我们证明没有任何划分是稳定的。这促使我们引入更受限（且更相关）的阻止概念；有趣的是，我们发现这些新稳定性概念下的稳定配置是双寡头，其中主导联盟利用其规模经济优势来占据不成比例的市场份额。此外，我们完整刻画了重流量和轻流量情况下稳定的双寡头结构。