Yingkai Li

AAAI Conference 2026 Conference Paper

Information Elicitation Mechanisms for Bayesian Auctions (Abstract Reprint)

• Jing Chen
• Bo Li
• Yingkai Li

In this paper we design information elicitation mechanisms for Bayesian auctions. While in Bayesian mechanism design the distributions of the players’ private types are often assumed to be common knowledge, information elicitation considers the situation where the players know the distributions better than the decision maker. To weaken the information assumption in Bayesian auctions, we consider an information structure where the knowledge about the distributions is arbitrarily scattered among the players. In such an unstructured information setting, we design mechanisms for unit-demand auctions and additive auctions that aggregate the players’ knowledge, generating revenue that are constant approximations to the optimal Bayesian mechanisms with a common prior. Our mechanisms are 2-step dominant-strategy truthful, and the approximation ratios improve gracefully with the amount of knowledge the players collectively have.

JAAMAS Journal 2025 Journal Article

Information elicitation mechanisms for Bayesian auctions

• Jing Chen
• Bo Li
• Yingkai Li

Abstract In this paper we design information elicitation mechanisms for Bayesian auctions. While in Bayesian mechanism design the distributions of the players’ private types are often assumed to be common knowledge, information elicitation considers the situation where the players know the distributions better than the decision maker. To weaken the information assumption in Bayesian auctions, we consider an information structure where the knowledge about the distributions is arbitrarily scattered among the players. In such an unstructured information setting, we design mechanisms for unit-demand auctions and additive auctions that aggregate the players’ knowledge, generating revenue that are constant approximations to the optimal Bayesian mechanisms with a common prior. Our mechanisms are 2-step dominant-strategy truthful and the approximation ratios improve gracefully with the amount of knowledge the players collectively have.

SODA Conference 2024 Conference Paper

Revenue Maximization for Buyers with Costly Participation

• Yannai A. Gonczarowski
• Nicole Immorlica
• Yingkai Li
• Brendan Lucier

SODA Conference 2023 Conference Paper

Simple Mechanisms for Non-linear Agents

• Yiding Feng 0001
• Jason D. Hartline
• Yingkai Li

We show that economic conclusions derived from Bulow and Roberts (1989) for linear utility models approximately extend to non-linear utility models. Specifically, we quantify the extent to which agents with non-linear utilities resemble agents with linear utilities, and we show that the approximation of mechanisms for agents with linear utilities approximately extend for agents with non-linear utilities. We illustrate the framework for the objectives of revenue and welfare on non-linear models that include agents with budget constraints, agents with risk aversion, and agents with endogenous valuations. We derive bounds on how much these models resemble the linear utility model and combine these bounds with well-studied approximation results for linear utility models. We conclude that simple mechanisms are approximately optimal for these non-linear agent models. * The full version of the paper can be accessed at https: //arxiv. org/abs/2003. 00545. This work is support by NSF CCF AF #1618502.

JAIR Journal 2023 Journal Article

Your College Dorm and Dormmates: Fair Resource Sharing with Externalities

• Jiarui Gan
• Bo Li
• Yingkai Li

We study a fair resource sharing problem, where a set of resources are to be shared among a group of agents. Each agent demands one resource and each resource can serve a limited number of agents. An agent cares about what resource they get as well as the externalities imposed by their mates, who share the same resource with them. Clearly, the strong notion of envy-freeness, where no agent envies another for their resource or mates, cannot always be achieved and we show that even deciding the existence of such a strongly envy-free assignment is an intractable problem. Hence, a more interesting question is whether (and in what situations) a relaxed notion of envy-freeness, the Pareto envyfreeness, can be achieved. Under this relaxed notion, an agent envies another only when they envy both the resource and the mates of the other agent. In particular, we are interested in a dorm assignment problem, where students are to be assigned to dorms with the same capacity and they have dichotomous preference over their dormmates. We show that when the capacity of each dorm is 2, a Pareto envy-free assignment always exists and we present a polynomial-time algorithm to compute such an assignment. Nevertheless, the result breaks immediately when the capacity increases to 3, in which case even Pareto envyfreeness cannot be guaranteed. In addition to the existential results, we also investigate the utility guarantees of (Pareto) envy-free assignments in our model.

AIJ Journal 2022 Journal Article

Bayesian auctions with efficient queries

• Jing Chen
• Bo Li
• Yingkai Li
• Pinyan Lu

IJCAI Conference 2022 Conference Paper

Bayesian Auctions with Efficient Queries (Extended Abstract)

• Jing Chen
• Bo Li
• Yingkai Li
• Pinyan Lu

Designing dominant-strategy incentive compatible (DSIC) mechanisms for a seller to generate (approximately) optimal revenue by selling items to players is a fundamental problem in Bayesian mechanism design. However, most existing studies assume that the seller knows the entire distribution from which the players’ values are drawn. Unfortunately, this assumption may not hold in reality: for example, when the distributions have exponentially large supports or do not have succinct representations. In this work we consider, for the first time, the query complexityof Bayesian mechanisms. The seller only has limited oracle accesses to the players’ distributions, via quantile queriesand value queries. For single-item auctions, we design mechanisms with logarithmicnumber of value or quantile queries which achieve almost optimal revenue. We then prove logarithmic lower-bounds, i. e. , logarithmic number of queries are necessary for any constant approximation DSIC mechanisms, even when randomized and adaptive queries are allowed. Thus our mechanisms are almost optimal regarding query complexity. Our lower-bounds can be extended to multi-item auctions with monotone subadditive valuations, and we complement this part with constant approximation mechanisms for unit-demand or additive valuation functions. Our results are robust even if the answers to the queries contain noises.

STOC Conference 2021 Conference Paper

Revelation gap for pricing from samples

• Yiding Feng 0001
• Jason D. Hartline
• Yingkai Li

FOCS Conference 2020 Conference Paper

Benchmark Design and Prior-independent Optimization

• Jason D. Hartline
• Aleck C. Johnsen
• Yingkai Li

This paper compares two leading approaches for robust optimization in the models of online algorithms and mechanism design. Competitive analysis compares the performance of an online algorithm to an offline benchmark in worst-case over inputs, and prior-independent mechanism design compares the expected performance of a mechanism on an unknown distribution (of inputs, i. e. , agent values) to the optimal mechanism for the distribution in worst case over distributions. For competitive analysis, a critical concern is the choice of benchmark. This paper gives a method for selecting a good benchmark. We show that optimal algorithm/mechanism for the optimal benchmark is equal to the prior-independent optimal algorithm/mechanism. We solve a central open question in prior-independent mechanism design, namely we identify the prior-independent revenue-optimal mechanism for selling a single item to two agents with i. i. d. and regularly distributed values. We use this solution to solve the corresponding benchmark design problem. Via this solution and the above equivalence of prior-independent mechanism design and competitive analysis (a. k. a. prior-free mechanism design) we show that the standard method for lower bounds of prior-free mechanisms is not generally tight for the benchmark design program. 1 1 For the full version of this work, see https: //arxiv. org/abs/2001. 10157.

ICML Conference 2020 Conference Paper

Multinomial Logit Bandit with Low Switching Cost

• Kefan Dong
• Yingkai Li
• Qin Zhang 0001
• Yuan Zhou 0007

We study multinomial logit bandit with limited adaptivity, where the algorithms change their exploration actions as infrequently as possible when achieving almost optimal minimax regret. We propose two measures of adaptivity: the assortment switching cost and the more fine-grained item switching cost. We present an anytime algorithm (AT-DUCB) with $O(N \log T)$ assortment switches, almost matching the lower bound $\Omega(\frac{N \log T}{ \log \log T})$. In the fixed-horizon setting, our algorithm FH-DUCB incurs $O(N \log \log T)$ assortment switches, matching the asymptotic lower bound. We also present the ESUCB algorithm with item switching cost $O(N \log^2 T)$.

IJCAI Conference 2019 Conference Paper

Approximately Maximizing the Broker's Profit in a Two-sided Market

• Jing Chen
• Bo Li
• Yingkai Li

We study how to maximize the broker's (expected) profit in a two-sided market, where she buys items from a set of sellers and resells them to a set of buyers. Each seller has a single item to sell and holds a private value on her item, and each buyer has a valuation function over the bundles of the sellers' items. We consider the Bayesian setting where the agents' values/valuations are independently drawn from prior distributions, and aim at designing dominant-strategy incentive-compatible (DSIC) mechanisms that are approximately optimal. Production-cost markets, where each item has a publicly-known cost to be produced, provide a platform for us to study two-sided markets. Briefly, we show how to covert a mechanism for production-cost markets into a mechanism for the broker, whenever the former satisfies cost-monotonicity. This reduction holds even when buyers have general combinatorial valuation functions. When the buyers' valuations are additive, we generalize an existing mechanism to production-cost markets in an approximation-preserving way. We then show that the resulting mechanism is cost-monotone and thus can be converted into an 8-approximation mechanism for two-sided markets.

AAMAS Conference 2019 Conference Paper

Revenue Maximization with Imprecise Distribution

• Yingkai Li
• Pinyan Lu
• Haoran Ye

We study the revenue maximization problem with an imprecisely estimated distribution of a single buyer or several independent and identically distributed buyers given that this estimation is not far away from the true distribution. We use the earth mover’s distance to capture the estimation error between those two distributions in terms of both values and their probabilities, i. e. , the error in value space given a quantile, and the error in quantile space given a value. We give explicit characterization of the optimal mechanisms for the single buyer setting. For the multi-buyer case, we provide an algorithm that finds an approximately optimal mechanism (FPTAS) among the family of second price mechanisms with a fixed reserve.

IJCAI Conference 2018 Conference Paper

Dynamic Fair Division Problem with General Valuations

• Bo Li
• Wenyang Li
• Yingkai Li

In this paper, we focus on how to dynamically allocate a divisible resource fairly among n players who arrive and depart over time. The players may have general heterogeneous valuations over the resource. It is known that the exact envy-free and proportional allocations may not exist in the dynamic setting [Walsh, 2011]. Thus, we will study to what extent we can guarantee the fairness in the dynamic setting. We first design two algorithms which are O(log n)-proportional and O(n)-envy-free for the setting with general valuations, and by constructing the adversary instances such that all dynamic algorithms must be at least Omega(1)-proportional and Omega(n/log n)-envy-free, we show that the bounds are tight up to a logarithmic factor. Moreover, we introduce the setting where the players' valuations are uniform on the resource but with different demands, which generalize the setting of [Friedman et al. , 2015]. We prove an O(log n) upper bound and a tight lower bound for this case.