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Lillian Ratliff

13 accepted papers

2026

Revisiting the Bertrand Paradox via Equilibrium Analysis of No-regret Learners

ICML 2026poster

We study the discrete Bertrand pricing game with a non-increasing demand function. The game has $n \ge 2$ players who simultaneously choose prices from the set {$1/k, 2/k, \ldots, 1$}, where $k\in\mathbb{N}$. The player who sets the lowest price captures the entire demand; if multiple players tie fo…

Cited by 0SourceScholar
2024

Efficient Interactive Maximization of BP and Weakly Submodular Objectives

UAI 2024poster

In the context of online interactive machine learning with combinatorial objectives, we extend purely submodular prior work to more general non-submodular objectives. This includes: (1) those that are additively decomposable into a sum of two terms (a monotone submodular and monotone supermodular t…

Cited by 0SourcePDFScholar
2024

Emergent specialization from participation dynamics and multi-learner retraining

AISTATS 2024poster

Numerous online services are data-driven: the behavior of users affects the system’s parameters, and the system’s parameters affect the users’ experience of the service, which in turn affects the way users may interact with the system. For example, people may choose to use a service only for tasks t…

2024

Near-Optimal Pure Exploration in Matrix Games: A Generalization of Stochastic Bandits & Dueling Bandits

AISTATS 2024poster

We study the sample complexity of identifying the pure strategy Nash equilibrium (PSNE) in a two-player zero-sum matrix game with noise. Formally, we are given a stochastic model where any learner can sample an entry $(i,j)$ of the input matrix $A\in [-1,1]^{n\times m}$ and observe $A_{i,j}+\eta$ wh…

2023

Approximate Regions of Attraction in Learning with Decision-Dependent Distributions

AISTATS 2023poster

As data-driven methods are deployed in real-world settings, the processes that generate the observed data will often react to the decisions of the learner. For example, a data source may have some incentive for the algorithm to provide a particular label (e.g. approve a bank loan), and manipulate th…

Cited by 13SourcePDFScholar
2023

Instance-dependent Sample Complexity Bounds for Zero-sum Matrix Games

AISTATS 2023poster

We study the sample complexity of identifying an approximate equilibrium for two-player zero-sum $n\times 2$ matrix games. That is, in a sequence of repeated game plays, how many rounds must the two players play before reaching an approximate equilibrium (e.g., Nash)? We derive instance-dependent bo…

Cited by 6SourcePDFScholar
2022

Learning in Stochastic Monotone Games with Decision-Dependent Data

AISTATS 2022poster

Learning problems commonly exhibit an interesting feedback mechanism wherein the population data reacts to competing decision makers’ actions. This paper formulates a new game theoretic framework for this phenomenon, called multi-player performative prediction. We establish transparent sufficient co…

Cited by 20SourcePDFScholar
2022

Zeroth-Order Methods for Convex-Concave Min-max Problems: Applications to Decision-Dependent Risk Minimization

AISTATS 2022poster

Min-max optimization is emerging as a key framework for analyzing problems of robustness to strategically and adversarially generated data. We propose the random reshuffling-based gradient-free Optimistic Gradient Descent-Ascent algorithm for solving convex-concave min-max problems with finite sum s…

Cited by 22SourcePDFScholar
2021

Evolutionary Game Theory Squared: Evolving Agents in Endogenously Evolving Zero-Sum Games

AAAI 2021technical

The predominant paradigm in evolutionary game theory and more generally online learning in games is based on a clear distinction between a population of dynamic agents that interact given a fixed, static game. In this paper, we move away from the artificial divide between dynamic agents and static g…

2020

Implicit Learning Dynamics in Stackelberg Games: Equilibria Characterization, Convergence Analysis, and Empirical Study

ICML 2020poster

Contemporary work on learning in continuous games has commonly overlooked the hierarchical decision-making structure present in machine learning problems formulated as games, instead treating them as simultaneous play games and adopting the Nash equilibrium solution concept. We deviate from this par…

Cited by 149SourcePDFScholar
2019

Convergence Analysis of Gradient-Based Learning in Continuous Games

UAI 2019poster

Considering a class of gradient-based multi-agent learning algorithms in non-cooperative settings, we provide convergence guarantees to a neighborhood of a stable Nash equilibrium. In particular, we consider continuous games where agents learn in 1) deterministic settings with oracle access to their…

Cited by 40SourcePDFScholar
2019

Sequential Experimental Design for Transductive Linear Bandits

NeurIPS 2019poster

In this paper we introduce the pure exploration transductive linear bandit problem: given a set of measurement vectors $\mathcal{X}\subset \mathbb{R}^d$, a set of items $\mathcal{Z}\subset \mathbb{R}^d$, a fixed confidence $\delta$, and an unknown vector $\theta^{\ast}\in \mathbb{R}^d$, the goal is…