Robustness of full revelation in multisender cheap talk
研究在二维发送者、多维廉价沟通中，当接收者对政策集有约束且对发送者偏差不确定时，完全揭示均衡的存在性与稳健性，给出了几何条件并构造了支持稳健均衡的政策规则。
This paper studies information transmission in a two‐sender, multidimensional cheap talk setting where there are exogenous constraints on the (convex) feasible set of policies for the receiver, and where the receiver is uncertain about both the directions and the magnitudes of the senders' bias vectors. With the supports of the biases represented by cones, we prove that whenever there exists an equilibrium that fully reveals the state, there exists a robust fully revealing equilibrium (FRE), i.e., one in which small deviations result in only small punishments. We provide a geometric condition—the local deterrence condition—that relates the cones of the biases to the frontier of the policy space, which is necessary and sufficient for the existence of a FRE. We also construct a specific policy rule for the receiver—the min rule—that supports a robust FRE whenever one exists.