Search Results for author: Christian Kroer

Found 25 papers, 0 papers with code

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.

Last-iterate Convergence in Extensive-Form Games

no code implementations27 Jun 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.

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.

Conic Blackwell Algorithm: Parameter-Free Convex-Concave Saddle-Point Solving

no code implementations27 May 2021 Julien Grand-Clément, Christian Kroer

We develop new parameter-free and scale-free algorithms for solving convex-concave saddle-point problems.

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).

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

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.

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

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.

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.

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

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.

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

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.

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.

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

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.

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.

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.

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.

Decision Making

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.

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.

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

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.

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.

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