This study explores how two competing port authorities facing ambiguity about uncertain market demands determine their optimal investments. Using the Choquet expected utility function, the port authorities are categorized into four types: ambiguity-averse and risk-averse, ambiguity-neutral and risk-averse, ambiguity-averse and risk-neutral, and ambiguity-neutral and risk-neutral. Each type can reach equilibria through no-port investing, only-one-port investing, or both-port investing. Our findings indicate that considering ambiguity does not alter the types of equilibrium investments for port authorities, regardless of their risk aversion or neutrality. However, the emergence of equilibrium investments for each type is affected by the consideration of ambiguity. Specifically, when risk-neutral port authorities transition from ambiguity-neutral to ambiguity-averse, they will invest more (less) if they are optimistic (pessimistic) enough. Nevertheless, this relationship may not apply to risk-averse port authorities, as the magnitudes of the first to the fourth moments of probability distributions, which maximize and minimize the expected utility of ports, also impact their investment decisions. Importantly, our results hold true even when ports exhibit ambiguity-loving characteristics, possess distinct ambiguity or risk attitudes, consider Knight uncertainty, or compete in prices.

本研究探讨了两个面临不确定市场需求模糊性的竞争港口当局如何确定其最佳投资。利用Choquet期望效用函数，将港口当局分为四种类型：模糊性厌恶和风险厌恶、模糊性中性和风险厌恶、模糊性厌恶和风险中性、模糊性中性和风险中性。每种类型都可以通过无端口投资、单端口投资或双端口投资达到均衡。我们的研究结果表明，考虑模糊性并不会改变港口当局的均衡投资类型，无论其风险规避或中立性如何。然而，每种类型均衡投资的出现都会受到模糊性考虑的影响。具体来说，当风险中性的港务局从模糊中性转向模糊厌恶时，如果足够乐观（悲观），他们就会增加（减少）投资。然而，这种关系可能不适用于规避风险的港口当局，因为概率分布的第一至第四矩的大小（最大化和最小化港口的预期效用）也会影响他们的投资决策。重要的是，即使港口表现出喜欢模糊性的特征、具有明显的模糊性或风险态度、考虑奈特不确定性或进行价格竞争，我们的结果仍然成立。