Stefanos Leonardos

Hello and welcome to my personal website!

I am a lecturer in machine learning at King’s College London, where I am very fortunate to lead the MAASAI (not the MAASAI) lab and co-lead the Informatics Finance Hub together with Bart de Keijzer and Carmine Ventre. I am also a member of the Distributed Artificial Intelligence research group, King’s Institute for Artificial Intelligence and the College’s Academic Board. Before coming to London, I spent four very memorable years as research fellow at Singapore University of Technology & Design hosted by Georgios Piliouras. I earned my PhD in game theory from the mathematics department of Athens University where I was very fortunate to be advised by Costis Melolidakis. My interests are in game theory, machine learning, artificial intelligence and cryptoeconomics. For my full list of publications please see my [CV] or [google scholar].

Contact details: King’s College London, Department of Informatics, Bush House, Office (S)5.13. email: [email protected].

For students:

Office hours (January-March 2026): Wednesdays 13:15-14:15 (right after the 7CCSMAMF tutorial). If you would like to book a slot, please email me first.
PhD positions: Currently, there are no funded PhD positions available. However, if you are interested in doing research in game theory, multi-agent systems, learning in games, reinforcement learning and/or cryptoeconomics (mechanism design/incentives), write to me about possible externally/self-funded PhD opportunities.
Thesis (MSc/BSc) supervision: Students taking the respective modules can find my thesis topic offerings, which cover similar topics to those listed above. I also welcome industry collaborations and student-proposed projects. For any questions, please email me.

Selected Publications (not actively updated – see Google scholar)

EICs 2023 selection @ ACM TEAC: Catastrophe by Design: A Mechanism to Destabilise Inefficient locked-in Technologies, J. Sakos, C. Courcoubetis, G. Piliouras.
Spotlight @ NeurIPS-21: Exploration-Exploitation in Multi-Agent Competition: Convergence with Bounded Rationality, G. Piliouras and K. Spendlove.
Best paper award @ AAAI-21: Exploration-Exploitation in Multiagent Learning: Catastrophe Theory Meets Game Theory, G. Piliouras.
Best paper award @ IEEE-TEM-20: PREStO: A Systematic Framework for Blockchain Consensus Protocols, D. Reijsbergen, G. Piliouras.
Best paper award @ Decentralized-20: Do Cryptocurrency Prices Camouflage Latent Economic Effects?, C. Koki, G. Piliouras.
Best paper award @ IEEE-ICBC-19: Weighted Voting on Blockchains: Improving Consensus in Proof of Stake Protocols, D. Reijsbergen, G. Piliouras.
Best paper award @ MARBLE-19: Oceanic Games: Centralization Risks and Incentives in Blockchain Mining, N. Leonardos, G. Piliouras.

Ethereum Collaboration (not actively updated – see Google scholar)

@ ICAIF-24, To Compete or Collude: Bidding Incentives in Ethereum Block Building Auctions, F. Wu, T. Thiery, C. Ventre.
@ CCE-23, Strategic Bidding Wars in On-chain Auctions, F. Wu, T. Thiery, C. Ventre.
@ FC-23, Optimality Despity Chaos in Fee Markets, D. Reijsbergen, B. Monnot, G. Piliouras.
@ IEEE-Blockchain-21, Transaction Fees on a Honeymoon: Ethereum’s EIP-1559 One Month Later, D. Reijsbergen, S. Shridhar, B. Monnot, S. Skoulakis, G. Piliouras.
@ AFT-21, Dynamical Analysis of the EIP-1559 Ethereum Fee Market, B. Monnot, D. Reijsbergen, S. Skoulakis, G. Piliouras.
@ WINE-20, Ethereum’s Transaction Fee Reform in EIP 1559, B. Monnot, Q. Z. Hum, C.S. M. Koh, G. Piliouras.
@ IEEE-ICBC-19, Incentives in Ethereum’s Hybrid Casper Protocol,V. Buterin, D. Reijsbergen, G. Piliouras.

News (old news – not actively updated)

@ FC-25: honored to join the program committee.
@ ICML 2025: honored to serve as an area chair.
@ AAAI-25: honored to join the program committee.
@ WWW-25: honored to serve as a reviewer.
@ NeurIPS-24: honored to serve as an area chair.
@ EC-24: honored to join the program committee.
@ ICLR-24: a new paper on equilibrium selection.
@ AAMAS-24: two new papers (here and here) on MEV and social dilemmas.
@ IEEE ICBC-24: a new paper on MEV-Boost auctions.
@ IJCAI 2024: honored to join the program committee.
@ ICML 2024: honored to join as a reviewer.
@ NeurIPS 2023: a new paper on offline reinforcement learning.
@ AAMAS 2024: honored to join the senior program committee.
@ ICLR 2024: honored to join as a reviewer.
@ Annals of Operations Research: a new paper on a useful generalization of the increasing generalized failure rate (IGFR) unimodality condition.
@ Workshop on Algorithms, Learning, and Games (ALGA): I accepted the kind invitation of Carmine Ventre to attend the ALGA workshop (and to eat lots of delicious pizza and pasta) between 04-09 June in Sicily, Italy!
@ NUS, Institute for Mathematical Studies: Excited to be invited to give a talk @ the Games, Learning, and Networks Workshop, 17-21 April 2023! Amazing to travel to Singapore again :)!
@ ACM TEAC: a new paper on catastrophe mechanism design in population games.
@ University of Leeds: Excited to be invited by Evangelos Pournaras to give a talk @ the School of Computing Colloquium series, on February 7 at 12pm, 2023 (in person).
@ University of Oxford: Excited to be invited by Andreas Galanis to give a talk at the Algorithm and Complexity Theory seminar series, on February 2 at 2pm, 2023 @ the Department of Computer Science (in person).
@ FC 2023: a new paper on optimality and chaos in transaction fee markets.
@ IJCAI 2023: I am delighted to join the program committee.
@ AAMAS 2023: I am delighted to join the program committee.
@ WINE 2022: I am delighted to join the program committee.
@ IJTCS 2022: Excited to give an invited talk at the Game Theory and Blockchain track, August 15-19, 2022, @ City University of Hong Kong (virtual).
@ MARBLE 2022: The technical program is now online! Exciting upcoming 100% physical event with tutorials, keynotes and fantastic activities!
@ ETHconomics – Devconnect April 21st, Amsterdam: I am excited to give a talk on the EIP-1559 transaction fee mechanism.
I will be giving an invited talk at the University of Edinburgh, School of Informatics on April 6.
Invited upcoming talks @ University of Southampton and @ King’s College London. Details coming soon.
@ AAMAS 2022: I am honored to join the PC of the Learning with Strategic Agents Workshop (LSA 2022).
Invited upcoming talks @ Royal Holloway University of London @ Tilburg University, @ Heriot-Watt University and @ Edindurgh Napier University.
Upcoming talk @ NKUA on April 1st (no lies :)): I will talk about our two papers [here] and [here] on Exploration-Exploitation in Multi-Agent Learning in the Statistics and Operations Research Seminar @ NKUA.
Upcoming talk @ SUTD on February 25th (virtual): I will present our recent works [here] and [here] (e-mail me for the link).
@ ACM DLT: I will be one of the guest editors in the special issue on Mathematical Research for Blockchain Economy! See the call for papers.
@ ICLR 2022: Global Convergence of Multi-Agent Policy Gradient in Markov Potential Games
@ Artificial Intelligence journal: the invited extended version of our AAAI article (see also this featured video) is forthcoming!
@ SAGT 2022: I am delighted to join as a PC member.
YouTube video of our AAAI talk by the State-of-the-Art AI Research channel.
@ MARBLE 2022: I am delighted to be TCP co-chair together with Elise Alfieri.
@ ICDCS 2022: I am delighted to join as a PC member.
@ IEEE Blockchain-2021: a new paper on Ethereum’s EIP-1559.
@ Research in International Business and Finance: Predictability of Cryptocurrencies via Bayesian Hidden Markov Models, C. Koki, G. Piliouras.
Talk @ ACM AFT-21: on our new paper about Ethereum’s EIP-1559.
@ ICML Workshop on RL: poster on the Convergence of Policy Gradient in Markov Potential Games, W. Overman, I. Panageas, G. Piliouras.
@ arXiv: From Griefing to Stability in Blockchain Mining Economies, Y.K. Cheung, S. Sridhar, G. Piliouras.
@ FOCODILE: contributed talk on our paper on EIP 1559 on June 18, 2021.
@ Economics Letters: Partial Passive Ownership Holdings, Licensing and Taxation, E. Petrakis, P. Skartados, G. Stamatopoulos.
Talk @ IJCAI-21: Learning in Markets, Y.K. Cheung, G. Piliouras.
@ Athens University of Economics and Business: talk on game theory and blockchains invited by E. Markakis on April 15, 2021.
Media coverage for our @ AAAI paper: [1,2,3,4].
Talk @ AAAI-21: on February 4, 2021, I will be presenting our [paper] on exploration – exploitation in multi-agent learning.
@ Annals of Operations Research: Monopoly Pricing in Vertical Markets with Demand Uncertainty, C. Melolidakis, C. Koki.
@ AtheCrypt2021: I am delighted to be invited to give talk on our [paper] on EIP 1559 on January 16, 2021.
@ European Journal of Operations Research: Strategic Customer Behavior, Y. Dimitrakopoulos, A. Economou.
@ WINE-20: contributed talks on our working papers at the Workshop on Blockchain and Game Theory.
Media coverage for our @ IEEE-ICBC paper: [1].
@ Ethereum: check out our new [paper] on Incentives in Ethereum’s Hybrid Casper Protocol, V. Buterin, D. Reijsbergen, G. Piliouras.
Media coverage for our @ MARBLE paper: [1,2].