Savage's P3 Is Redundant
证明萨维奇期望效用公理体系中的P3公理可由其他公理推导出，从而揭示其冗余性，这对决策理论研究者有参考价值。
Savage (1954) provided the first axiomatic characterization of expected utility without relying on any given probabilities or utilities. It is the most famous preference axiomatization existing. This note shows that Savage's axiom P3 is implied by the other axioms, which reveals its redundancy. It is remarkable that this was not noticed before as Savage's axiomatization has been studied and taught by hundreds of researchers for more than six decades.