Alexandros Tsigonias-Dimitriadis

Alexandros Tsigonias-Dimitriadis

Graduate Programme Participant, European Central Bank

Hi, I’m Alexandros!

I am currently a Graduate Programme Participant at the European Central Bank. This is a selective programme for recent (PhD) graduates, which involves two one-year assignments in two different business areas and submitting a paper at the end of the programme for evaluation. My first-year allocation was in Risk Management. I am spending my second year in Information Systems, contributing to the development of AI/ML-driven applications for Banking Supervision.

Before coming to the ECB, I was a postdoctoral researcher at the Department of Industrial Engineering of the University of Chile hosted by Prof. José Correa. I obtained my PhD from the Department of Mathematics of the TUM School of Computation, Information and Technology. At TU Munich, I was advised by Prof. Andreas S. Schulz and was a member of the interdisciplinary research group Advanced Optimization in a Networked Economy (AdONE) and the Operations Research Group. During my PhD and postdoc, I had the opportunity to spend some time at Google Research Zurich and the Sapienza University of Rome. I received my Diploma (BSc and MEng equivalent) in Electrical and Computer Engineering from the National Technical University of Athens, where I was advised by Prof. Dimitris Fotakis.

My research during my PhD and postdoc revolved mainly around the design of algorithms and mechanisms for fair and efficient resource allocation with applications in pricing, recommender systems, apportionment, and generally complex scenarios arising in (online) markets and platforms. To study these problems, I have used a broad set of tools from algorithms, economics, operations, mechanism design, machine learning, and optimization. During my first year at the ECB, I also started working on topics related to computational social science and central banking communication, using natural language processing and econometric methods.

I’m still trying to allocate a fraction of my time to research. This page serves mainly for posting updates related to my research papers, and keeping all the material related to them so that they can be accessed easily.

You can find a copy of my CV here (last update: September 2025).

Interests
  • Economics and Computation
  • Operations Research & Optimization
  • AI & Machine Learning
  • Computational Social Science
Education
  • PhD in Mathematics, 2022

    Technical University of Munich

  • Diploma in Electrical and Computer Engineering, 2018

    National Technical University of Athens

News

  • [September 2025] Our paper on monotone apportioment has been accepted for publicationin Mathematics of Operations Research!

  • [June 2025] Our paper on the Prophet Secretary Against the Online Optimal has been accepted in Mathematics of Operations Research!

  • [February 2025] Check this very nice short article from MPI, where Javier talks about our SODA paper on apportionment.

  • [February 2025] Paper accepted in ACM TEAC.

  • [October 2024] Our paper on monotone apportionment methods will appear in SODA25!

  • [September 2024] I just started the ECB Graduate Programme!

  • [June 2024] The journal version of our paper “The Secretary Problem with Independent Sampling” has been published in Management Science! You can find it here. A big thank you to my co-authors for this wonderful collaboration!

  • [September 2023] Our paper with Tomer, Stefano, Rebecca, and Matteo has been accepted to WINE 2023!

  • [July 2023] I just started a new position at the European Central Bank!

  • [May 2023] I just started a research visit at Google Zurich hosted by Paul Dütting! I will be here for two months working on exciting algorithmic questions.

  • [May 2023] Our paper on the Prophet Secretary problem with Paul, Evangelia, Rojin, and Yifeng has been accepted to EC ‘23! We will post the full paper very soon on arXiv.

Journal Articles

(2025). New Combinatorial Insights for Monotone Apportionment. Accepted, Mathematics of Operations Research.

(2025). Prophet Secretary Against the Online Optimal. Accepted, Mathematics of Operations Research.

(2025). The Secretary Problem with Independent Sampling. Management Science.

DOI Paper Appendix

(2025). Prophet Inequalities via the Expected Competitive Ratio. ACM Transactions on Economics and Computation (ACM TEAC).

DOI

(2022). Robust Revenue Maximization Under Minimal Statistical Information. ACM Transactions on Economics and Computation (ACM TEAC).

Cite DOI arXiv

Conference Publications

(2025). New Combinatorial Insights for Monotone Apportionment. In the proceedings of the 2025 ACM-SIAM Symposium on Discrete Algorithms (SODA ‘25).

DOI arXiv MPI article

(2023). Prophet Inequalities via the Expected Competitive Ratio. Extended abstract in the 19th Conference on Web and Internet Economics (WINE ‘23).

DOI arXiv slides

(2023). Prophet Secretary Against the Online Optimal. In the proceedings of the 24th Conference on Economics and Computation (EC ‘23).

arXiv DOI poster

(2021). The Secretary Problem with Independent Sampling. Extended abstract in the 2021 ACM-SIAM Symposium on Discrete Algorithms (SODA ‘21).

DOI arXiv slides poster

(2020). Robust Revenue Maximization Under Minimal Statistical Information. Extended abstract in the 16th Conference on Web and Internet Economics (WINE ‘20).

DOI slides video

Working Papers & Manuscripts

(2025). Online Policies for Content Recommendation with Fairness Constraints. Submitted.

(2023). Preference Elicitation in Combinatorial Auctions: An Improved Approach using Reinforcement Learning. Manuscript.

Teaching / Supervision

I have been a teaching assistant for the following courses:

I have co-supervised Master theses on the following topics:

  • Unified Voice or Cacophony? A Discordance Index of the European Central Bank Governing Council Members, ECB & Barcelona School of Economics
  • Iterative Combinatorial Auctions: Improved Running Time via Machine Learning, TUM
  • Experimental Evaluation of Robust Revenue-Maximizing Auctions, TUM

Contact