Search Results for author: Christian Kroer

Found 39 papers, 2 papers with code

Arbitrage-Free Combinatorial Market Making via Integer Programming

no code implementations9 Jun 2016 Christian Kroer, Miroslav Dudík, Sébastien Lahaie, Sivaraman Balakrishnan

We present a new combinatorial market maker that operates arbitrage-free combinatorial prediction markets specified by integer programs.

Theoretical and Practical Advances on Smoothing for Extensive-Form Games

no code implementations16 Feb 2017 Christian Kroer, Kevin Waugh, Fatma Kilinc-Karzan, Tuomas Sandholm

By introducing a new weighting scheme for the dilated entropy function, we develop the first distance-generating function for the strategy spaces of sequential games that has no dependence on the branching factor of the player.

counterfactual

Multiplicative Pacing Equilibria in Auction Markets

no code implementations22 Jun 2017 Vincent Conitzer, Christian Kroer, Eric Sodomka, Nicolas E. Stier-Moses

Although we show that computing either a social-welfare-maximizing or a revenue-maximizing pacing equilibrium is NP-hard, we present a mixed-integer program (MIP) that can be used to find equilibria optimizing several relevant objectives.

Computer Science and Game Theory

Regret Minimization in Behaviorally-Constrained Zero-Sum Games

no code implementations ICML 2017 Gabriele Farina, Christian Kroer, Tuomas Sandholm

We use an instantiation of the CFR framework to develop algorithms for solving behaviorally-constrained (and, as a special case, perturbed in the Selten sense) extensive-form games, which allows us to compute approximate Nash equilibrium refinements.

counterfactual

Robust Stackelberg Equilibria in Extensive-Form Games and Extension to Limited Lookahead

no code implementations21 Nov 2017 Christian Kroer, Gabriele Farina, Tuomas Sandholm

We then extend the program to the robust setting for Stackelberg equilibrium under unlimited and under limited lookahead by the opponent.

Online Convex Optimization for Sequential Decision Processes and Extensive-Form Games

no code implementations10 Sep 2018 Gabriele Farina, Christian Kroer, Tuomas Sandholm

Experiments show that our framework leads to algorithms that scale at a rate comparable to the fastest variants of counterfactual regret minimization for computing Nash equilibrium, and therefore our approach leads to the first algorithm for computing quantal response equilibria in extremely large games.

counterfactual Decision Making

Solving Large Sequential Games with the Excessive Gap Technique

no code implementations NeurIPS 2018 Christian Kroer, Gabriele Farina, Tuomas Sandholm

We present, to our knowledge, the first GPU implementation of a first-order method for extensive-form games.

counterfactual

Regret Circuits: Composability of Regret Minimizers

no code implementations6 Nov 2018 Gabriele Farina, Christian Kroer, Tuomas Sandholm

We show that local regret minimizers for the simpler sets can be combined with additional regret minimizers into an aggregate regret minimizer for the composite set.

A Unified Framework for Extensive-Form Game Abstraction with Bounds

no code implementations NeurIPS 2018 Christian Kroer, Tuomas Sandholm

In this paper we present a unified framework for analyzing abstractions that can express all types of abstractions and solution concepts used in prior papers with performance guarantees---while maintaining comparable bounds on abstraction quality.

Computing large market equilibria using abstractions

no code implementations18 Jan 2019 Christian Kroer, Alexander Peysakhovich, Eric Sodomka, Nicolas E. Stier-Moses

Computing market equilibria is an important practical problem for market design, for example in fair division of items.

Matrix Completion

Stable-Predictive Optimistic Counterfactual Regret Minimization

no code implementations13 Feb 2019 Gabriele Farina, Christian Kroer, Noam Brown, Tuomas Sandholm

The CFR framework has been a powerful tool for solving large-scale extensive-form games in practice.

counterfactual

Limited Lookahead in Imperfect-Information Games

no code implementations17 Feb 2019 Christian Kroer, Tuomas Sandholm

We characterize the hardness of finding a Nash equilibrium or an optimal commitment strategy for either player, showing that in some of these variations the problem can be solved in polynomial time while in others it is PPAD-hard, NP-hard, or inapproximable.

Increasing Iterate Averaging for Solving Saddle-Point Problems

no code implementations26 Mar 2019 Yuan Gao, Christian Kroer, Donald Goldfarb

In particular, the increasing averages consistently outperform the uniform averages in all test problems by orders of magnitude.

Image Denoising

Robust Multi-agent Counterfactual Prediction

no code implementations NeurIPS 2019 Alexander Peysakhovich, Christian Kroer, Adam Lerer

We consider the problem of using logged data to make predictions about what would happen if we changed the `rules of the game' in a multi-agent system.

counterfactual

Fair Division Without Disparate Impact

no code implementations6 Jun 2019 Alexander Peysakhovich, Christian Kroer

We consider the problem of dividing items between individuals in a way that is fair both in the sense of distributional fairness and in the sense of not having disparate impact across protected classes.

Fairness Recommendation Systems

Optimistic Regret Minimization for Extensive-Form Games via Dilated Distance-Generating Functions

no code implementations NeurIPS 2019 Gabriele Farina, Christian Kroer, Tuomas Sandholm

Our algorithms provably converge at a rate of $T^{-1}$, which is superior to prior counterfactual regret minimization algorithms.

counterfactual

Stochastic Regret Minimization in Extensive-Form Games

no code implementations ICML 2020 Gabriele Farina, Christian Kroer, Tuomas Sandholm

Our framework allows us to instantiate several new stochastic methods for solving sequential games.

counterfactual

Scalable First-Order Methods for Robust MDPs

no code implementations11 May 2020 Julien Grand-Clément, Christian Kroer

Our framework is also the first one to solve robust MDPs with $s$-rectangular KL uncertainty sets.

Decision Making

Evaluating and Rewarding Teamwork Using Cooperative Game Abstractions

no code implementations NeurIPS 2020 Tom Yan, Christian Kroer, Alexander Peysakhovich

We apply our methods to study teams of artificial RL agents as well as real world teams from professional sports.

Dominant Resource Fairness with Meta-Types

no code implementations21 Jul 2020 Steven Yin, Shatian Wang, Lingyi Zhang, Christian Kroer

Inspired by the recent COVID-19 pandemic, we study a generalization of the multi-resource allocation problem with heterogeneous demands and Leontief utilities.

Fairness

Faster Game Solving via Predictive Blackwell Approachability: Connecting Regret Matching and Mirror Descent

no code implementations28 Jul 2020 Gabriele Farina, Christian Kroer, Tuomas Sandholm

In spite of this prevalence, the regret matching (RM) and regret matching+ (RM+) algorithms have been preferred in the practice of solving large-scale games (as the local regret minimizers within the counterfactual regret minimization framework).

counterfactual

Better Regularization for Sequential Decision Spaces: Fast Convergence Rates for Nash, Correlated, and Team Equilibria

no code implementations27 May 2021 Gabriele Farina, Christian Kroer, Tuomas Sandholm

The scaled extension operator is a way to recursively construct convex sets, which generalizes the decision polytope of extensive-form games, as well as the convex polytopes corresponding to correlated and team equilibria.

Last-iterate Convergence in Extensive-Form Games

no code implementations NeurIPS 2021 Chung-Wei Lee, Christian Kroer, Haipeng Luo

Inspired by recent advances on last-iterate convergence of optimistic algorithms in zero-sum normal-form games, we study this phenomenon in sequential games, and provide a comprehensive study of last-iterate convergence for zero-sum extensive-form games with perfect recall (EFGs), using various optimistic regret-minimization algorithms over treeplexes.

counterfactual

Matching Algorithms for Blood Donation

no code implementations10 Aug 2021 Duncan C McElfresh, Christian Kroer, Sergey Pupyrev, Eric Sodomka, Karthik Sankararaman, Zack Chauvin, Neil Dexter, John P Dickerson

Using the Facebook Blood Donation tool, we conduct the first large-scale algorithmic matching of blood donors with donation opportunities.

Faster No-Regret Learning Dynamics for Extensive-Form Correlated Equilibrium

no code implementations29 Sep 2021 Ioannis Anagnostides, Gabriele Farina, Christian Kroer, Tuomas Sandholm

A recent emerging trend in the literature on learning in games has been concerned with providing accelerated learning dynamics for correlated and coarse correlated equilibria in normal-form games.

Kernelized Multiplicative Weights for 0/1-Polyhedral Games: Bridging the Gap Between Learning in Extensive-Form and Normal-Form Games

no code implementations1 Feb 2022 Gabriele Farina, Chung-Wei Lee, Haipeng Luo, Christian Kroer

In this paper we show that the Optimistic Multiplicative Weights Update (OMWU) algorithm -- the premier learning algorithm for NFGs -- can be simulated on the normal-form equivalent of an EFG in linear time per iteration in the game tree size using a kernel trick.

Single-Leg Revenue Management with Advice

no code implementations18 Feb 2022 Santiago Balseiro, Christian Kroer, Rachitesh Kumar

Moreover, we provide an online algorithm that always achieves performance on this Pareto frontier.

Management

Solving optimization problems with Blackwell approachability

no code implementations24 Feb 2022 Julien Grand-Clément, Christian Kroer

We introduce the Conic Blackwell Algorithm$^+$ (CBA$^+$) regret minimizer, a new parameter- and scale-free regret minimizer for general convex sets.

Best of Many Worlds Guarantees for Online Learning with Knapsacks

no code implementations28 Feb 2022 Andrea Celli, Matteo Castiglioni, Christian Kroer

We study online learning problems in which a decision maker wants to maximize their expected reward without violating a finite set of $m$ resource constraints.

Uncoupled Learning Dynamics with $O(\log T)$ Swap Regret in Multiplayer Games

no code implementations25 Apr 2022 Ioannis Anagnostides, Gabriele Farina, Christian Kroer, Chung-Wei Lee, Haipeng Luo, Tuomas Sandholm

In this paper we establish efficient and \emph{uncoupled} learning dynamics so that, when employed by all players in a general-sum multiplayer game, the \emph{swap regret} of each player after $T$ repetitions of the game is bounded by $O(\log T)$, improving over the prior best bounds of $O(\log^4 (T))$.

A Unified Approach to Reinforcement Learning, Quantal Response Equilibria, and Two-Player Zero-Sum Games

3 code implementations12 Jun 2022 Samuel Sokota, Ryan D'Orazio, J. Zico Kolter, Nicolas Loizou, Marc Lanctot, Ioannis Mitliagkas, Noam Brown, Christian Kroer

This work studies an algorithm, which we call magnetic mirror descent, that is inspired by mirror descent and the non-Euclidean proximal gradient algorithm.

MuJoCo Games reinforcement-learning +1

Near-Optimal No-Regret Learning Dynamics for General Convex Games

no code implementations17 Jun 2022 Gabriele Farina, Ioannis Anagnostides, Haipeng Luo, Chung-Wei Lee, Christian Kroer, Tuomas Sandholm

In this paper, we answer this in the positive by establishing the first uncoupled learning algorithm with $O(\log T)$ per-player regret in general \emph{convex games}, that is, games with concave utility functions supported on arbitrary convex and compact strategy sets.

Online Resource Allocation under Horizon Uncertainty

no code implementations27 Jun 2022 Santiago Balseiro, Christian Kroer, Rachitesh Kumar

We go on to give a fast algorithm for computing a schedule of target consumption rates that leads to near-optimal performance in the unknown-horizon setting.

Management

Computing the optimal distributionally-robust strategy to commit to

1 code implementation15 Sep 2022 Sai Mali Ananthanarayanan, Christian Kroer

In the security setting, the goal is for the leader to compute an optimal strategy to commit to, in order to protect some asset.

Optimal Efficiency-Envy Trade-Off via Optimal Transport

no code implementations25 Sep 2022 Steven Yin, Christian Kroer

We consider the problem of allocating a distribution of items to $n$ recipients where each recipient has to be allocated a fixed, prespecified fraction of all items, while ensuring that each recipient does not experience too much envy.

Statistical Inference for Fisher Market Equilibrium

no code implementations29 Sep 2022 Luofeng Liao, Yuan Gao, Christian Kroer

In resource allocation, it is crucial to quantify the variability of the resource received by the agents (such as blood banks and food banks) in addition to fairness and efficiency properties of the systems.

Fairness Management

Online Learning under Budget and ROI Constraints via Weak Adaptivity

no code implementations2 Feb 2023 Matteo Castiglioni, Andrea Celli, Christian Kroer

Finally, we show how to instantiate the framework to optimally bid in various mechanisms of practical relevance, such as first- and second-price auctions.

Last-Iterate Convergence Properties of Regret-Matching Algorithms in Games

no code implementations1 Nov 2023 Yang Cai, Gabriele Farina, Julien Grand-Clément, Christian Kroer, Chung-Wei Lee, Haipeng Luo, Weiqiang Zheng

Algorithms based on regret matching, specifically regret matching$^+$ (RM$^+$), and its variants are the most popular approaches for solving large-scale two-player zero-sum games in practice.

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