查看更多>>摘要：We investigate a cheap talk model in which a decision maker and an expert are both privately informed. Both players observe independent signals that jointly determine ideal actions for the players, and the decision maker can send a cheap talk message to the expert, which is followed by the cheap talk of the expert and then the action of the decision maker. In equilibrium, the strategy of the decision maker is not monotonic, and the revelation of the decision maker concerning her information does not necessarily result in welfare improvement of the players. In particular, in models in which optimal actions are additively and/or multiplicatively separable in the information of two players and their preferences are represented by quadratic loss functions, the information revelation of the decision maker cannot facilitate information transmitted from the expert. (C) 2022 Elsevier Inc. All rights reserved.
查看更多>>摘要：We consider games in which an informed sender first talks at no cost to a receiver; then, the latter proposes a decision and, finally, the sender accepts the proposal or "exits ". We make the following assumptions: the sender has finitely many types, the receiver's decision is real-valued, utility functions over decisions are concave, single-peaked and single-crossing, exit is damaging to the receiver. In this setup, it may happen that babbling equilibria necessarily involve exit. We nevertheless propose a constructive algorithm that achieves a pure perfect Bayesian equilibrium without exit in every game of the class considered.(c) 2022 Elsevier Inc. All rights reserved.
查看更多>>摘要：We show how symmetric equilibria emerge in general two-player contests in which skill and effort are combined to produce output according to a general production technology and players have skills drawn from different distributions. The model includes the Tullock (1980) and Lazear and Rosen (1981) models as special cases. Our paper provides intuition regarding how the contest components interact to determine the incentive to exert effort and sheds new light on classic comparative statics results. In particular, we show that more heterogeneity can increase equilibrium effort.(c) 2022 The Author(s). Published by Elsevier Inc. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/).
查看更多>>摘要：Consider a monopolist selling n items to an additive buyer whose item values are drawn from independent distributions F-1, F-2, ..., F-n possibly having unbounded support. Unlike in the single-item case, it is well known that the revenue-optimal selling mechanism (a pricing scheme) may be complex, sometimes requiring a continuum of menu entries. Also known is that simple mechanisms with a bounded number of menu entries can extract a constant fraction of the optimal revenue. Nonetheless, whether an arbitrarily high fraction of the optimal revenue can be extracted via a bounded menu size remained open. We give an affirmative answer: for every n and epsilon > 0, there exists C = C(n, epsilon) s.t. mechanisms of menu size at most C suffice for obtaining (1 - epsilon) of the optimal revenue from any F-1, ..., F-n. We prove upper and lower bounds on the revenue-approximation complexity C(n, epsilon) and on the deterministic communication complexity required to run a mechanism achieving such an approximation. (C) 2021 Elsevier Inc. All rights reserved.
查看更多>>摘要：A large line of recent work studies the welfare guarantees of simple and prevalent combinatorial auction formats, such as selling m items via simultaneous second price auctions (SiSPAs). These guarantees hold even when the auctions are repeatedly executed and the players use no-regret learning algorithms. Unfortunately, off-the-shelf no-regret algorithms for these auctions are computationally inefficient. We show that this obstacle is insurmountable: there are no polynomial-time no-regret algorithms for SiSPAs, unless RP & SUPE; NP, even when bidders are unit-demand. Our lower bound raises the question of how good outcomes polynomially-bounded bidders may discover in such auctions. We propose a novel concept of learning in auctions, termed "no-envy learning ", and show that it is both efficiently implementable and results in approximately optimal welfare, even when the bidders have valuations from the broad class of fractionally subadditive valuations, assuming demand oracle access to the valuations, or coverage valuations, even without demand oracles.(c) 2022 Elsevier Inc. All rights reserved.
Sivan, BalasubramanianChawla, ShuchiDevanur, Nikhil R.Karlin, Anna R....
17页
查看更多>>摘要：We consider a pricing problem where a buyer is interested in purchasing/using a good, such as an app or music or software, repeatedly over time. The consumer discovers his value for the good only as he uses it, and the value evolves with each use. In this paper, we explore the performance of a class of pricing mechanisms that are extremely simple for both the buyer and the seller to use: the seller offers the product for free for a certain number of uses, and then charges an appropriate fixed price per usage. The buyer reacts to prices myopically without worrying about how his value evolves in the future. We show that under certain assumptions, a pricing mechanism of this form is approximately optimal regardless of the buyer's risk profile or fine details of the value evolution process.(c) 2022 Elsevier Inc. All rights reserved.
Dvijotham, KrishnamurthyRabani, YuvalSchulman, Leonard J.
15页
查看更多>>摘要：We study out-of-equilibrium price dynamics in Fisher markets. We develop a general framework in which sellers have (a) a set of atomic price update rules (APU), which are simple responses to a price vector; (b) a belief-formation procedure that simulates actions of other sellers (themselves using the APU) to some finite horizon in the future. Sellers use an APU to respond to a price vector they generate with the belief formation procedure. The framework allows sellers to have inconsistent and time-varying beliefs about each other. Under mild and natural assumptions on the APU, we show that despite the inconsistent and time-varying nature of beliefs, the market converges to a unique equilibrium at a linear rate (distance to equilibrium decreases exponentially in time). If the APU are driven by weak gross substitutes demands, the equilibrium point is the same as predicted by those demands.(c) 2020 Elsevier Inc. All rights reserved.
查看更多>>摘要：For a constant c, we prove a poly(N) lower bound on the (randomized) communication complexity of c-Nash equilibrium in two-player N x N games. For n-player binary-action games we prove an exp(n) lower bound for the (randomized) communication complexity of (c, 0-weak approximate Nash equilibrium, which is a profile of mixed actions such that at least (1 - 0-fraction of the players are c-best replying. (c) 2020 Elsevier Inc. All rights reserved.
查看更多>>摘要：We introduce a simple dynamic mechanism design problem in which the designer offers two items in two consecutive stages to a single buyer. The buyer's joint distribution of valuations for the two items is known, and the buyer knows the valuation for the current item, but not for the one in the future. The designer seeks to maximize expected revenue, and the mechanism must be deterministic, truthful, and ex-post individually rational. We show that finding the optimum deterministic mechanism in this situation - arguably one of the simplest meaningful dynamic mechanism design problems imaginable - is NP-hard. We also prove several positive results, including a polynomial-time linear programming based algorithm for the revenue optimal randomized mechanism (even for many buyers and many stages). We prove strong separations in revenue between non-adaptive, adaptive, and randomized mechanisms, even when the valuations in the two stages are independent.(c) 2022 Elsevier Inc. All rights reserved.
查看更多>>摘要：In a combinatorial auction with item bidding, agents participate in multiple single-item second-price auctions at once. As some items might be substitutes, agents need to strategize in order to maximize their utilities. A number of results indicate that high social welfare can be achieved this way, giving bounds on the welfare at equilibrium. Recently, however, criticism has been raised that equilibria of this game are hard to compute and therefore unlikely to be attained. In this paper, we take a different perspective by studying simple best-response dynamics. Often these dynamics may take exponentially long before they converge or they may not converge at all. However, as we show, convergence is not even necessary for good welfare guarantees. Given that agents' bid updates are aggressive enough but not too aggressive, the game will reach and remain in states of high welfare after each agent has updated his bid at least once.
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