activity
20212026
most citedOn Last-Iterate Convergence Beyond Zero-Sum Games

6 citations · 12 across the 16 of their papers we have counts for

collaborators

18 papers

cs.GT2026

The Complexity of Nash Equilibrium in Network Congestion and Coordination Games

Ioannis Anagnostides, Ioannis Panageas, Jingming Yan

We show that computing a Nash equilibrium is CLS-complete for linear network congestion and network coordination games. As a result, finding a KKT point of a bilinear polynomial is…

cs.GT2026

The Computational Complexity of Team Zero-Sum Games

Ioannis Anagnostides, Ioannis Panageas, Tuomas Sandholm +1

A celebrated consequence of the minimax theorem is that two-player zero-sum games admit a tractable equilibrium characterization. In many central applications, however, each side c…

cs.GT2026

Convex Markov Games and Beyond: New Proof of Existence, Characterization and Learning Algorithms for Nash Equilibria

Anas Barakat, Ioannis Panageas, Antonios Varvitsiotis

Convex Markov Games (cMGs) were recently introduced as a broad class of multi-agent learning problems that generalize Markov games to settings where strategic agents optimize gener…

cs.GT2026

(Doubly) Exponential Lower Bounds for Follow the Regularized Leader in Potential Games

Ioannis Anagnostides, Ioannis Panageas, Nikolas Patris +1

Follow the regularized leader FTRL is the premier algorithm for online optimization. However, despite decades of research on its convergence in constrained optimization -- and pote…

cs.LG2026

On the Computational Complexity of Performative Prediction

Ioannis Anagnostides, Rohan Chauhan, Ioannis Panageas +2

Performative prediction captures the phenomenon where deploying a predictive model shifts the underlying data distribution. While simple retraining dynamics are known to converge l…

cs.GT2025

Convergence of Regret Matching in Potential Games and Constrained Optimization

Ioannis Anagnostides, Emanuel Tewolde, Brian Hu Zhang +3

Regret matching (RM) -- and its modern variants -- is a foundational online algorithm that has been at the heart of many AI breakthrough results in solving benchmark zero-sum games…

cs.GT2025

The Complexity of Symmetric Equilibria in Min-Max Optimization and Team Zero-Sum Games

Ioannis Anagnostides, Ioannis Panageas, Tuomas Sandholm +1

We consider the problem of computing stationary points in min-max optimization, with a particular focus on the special case of computing Nash equilibria in (two-)team zero-sum game…

cs.GT2024

Learning Equilibria in Adversarial Team Markov Games: A Nonconvex-Hidden-Concave Min-Max Optimization Problem

Fivos Kalogiannis, Jingming Yan, Ioannis Panageas

We study the problem of learning a Nash equilibrium (NE) in Markov games which is a cornerstone in multi-agent reinforcement learning (MARL). In particular, we focus on infinite-ho…

cs.GT2024

Computing Nash Equilibria in Potential Games with Private Uncoupled Constraints

Nikolas Patris, Stelios Stavroulakis, Fivos Kalogiannis +2

We consider the problem of computing Nash equilibria in potential games where each player's strategy set is subject to private uncoupled constraints. This scenario is frequently en…

cs.GT2023

Optimistic Policy Gradient in Multi-Player Markov Games with a Single Controller: Convergence Beyond the Minty Property

Ioannis Anagnostides, Ioannis Panageas, Gabriele Farina +1

Policy gradient methods enjoy strong practical performance in numerous tasks in reinforcement learning. Their theoretical understanding in multiagent settings, however, remains lim…

cs.GT2023★ 1 cited

Zero-sum Polymatrix Markov Games: Equilibrium Collapse and Efficient Computation of Nash Equilibria

Fivos Kalogiannis, Ioannis Panageas

The works of (Daskalakis et al., 2009, 2022; Jin et al., 2022; Deng et al., 2023) indicate that computing Nash equilibria in multi-player Markov games is a computationally hard tas…

cs.LG2023★ 2 cited

On the Convergence of No-Regret Learning Dynamics in Time-Varying Games

Ioannis Anagnostides, Ioannis Panageas, Gabriele Farina +1

Most of the literature on learning in games has focused on the restrictive setting where the underlying repeated game does not change over time. Much less is known about the conver…

cs.GT2023

Algorithms and Complexity for Computing Nash Equilibria in Adversarial Team Games

Ioannis Anagnostides, Fivos Kalogiannis, Ioannis Panageas +2

Adversarial team games model multiplayer strategic interactions in which a team of identically-interested players is competing against an adversarial player in a zero-sum game. Suc…

cs.GT2022★ 2 cited

Efficiently Computing Nash Equilibria in Adversarial Team Markov Games

Fivos Kalogiannis, Ioannis Anagnostides, Ioannis Panageas +3

Computing Nash equilibrium policies is a central problem in multi-agent reinforcement learning that has received extensive attention both in theory and in practice. However, provab…

cs.GT2022★ 6 cited

On Last-Iterate Convergence Beyond Zero-Sum Games

Ioannis Anagnostides, Ioannis Panageas, Gabriele Farina +1

Most existing results about \emph{last-iterate convergence} of learning dynamics are limited to two-player zero-sum games, and only apply under rigid assumptions about what dynamic…

cs.GT2022★ 1 cited

Optimistic Mirror Descent Either Converges to Nash or to Strong Coarse Correlated Equilibria in Bimatrix Games

Ioannis Anagnostides, Gabriele Farina, Ioannis Panageas +1

We show that, for any sufficiently small fixed , when both players in a general-sum two-player (bimatrix) game employ optimistic mirror descent (OMD) with smooth regularizati…

cs.GT2021

Towards convergence to Nash equilibria in two-team zero-sum games

Fivos Kalogiannis, Ioannis Panageas, Emmanouil-Vasileios Vlatakis-Gkaragkounis

Contemporary applications of machine learning in two-team e-sports and the superior expressivity of multi-agent generative adversarial networks raise important and overlooked theor…

math.OC2021

Frequency-Domain Representation of First-Order Methods: A Simple and Robust Framework of Analysis

Ioannis Anagnostides, Ioannis Panageas

Motivated by recent applications in min-max optimization, we employ tools from nonlinear control theory in order to analyze a class of "historical" gradient-based methods, for whic…