Alkis Kalavasis

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Hi! I am an FDS Postdoctoral Fellow at Yale University. Before that, I was a PhD student in the Computer Science Department of the National Technical University of Athens (NTUA) working with Dimitris Fotakis and Christos Tzamos. I completed my undergraduate studies in the School of Electrical and Computer Engineering Department of the NTUA, where I was advised by Dimitris Fotakis.

Research: My research focuses on Machine Learning Theory and its interplay with Statistics & High-Dimensional Probability, Optimization and Computational Complexity. Currently, I am interested in questions regarding the following topics:
  1. Robustness and Stability in Learning: Inference from Biased Data, Privacy, Replicability, Transfer Learning
  2. Statistical Learning Theory: PAC Learning, Universal Learning, Distribution Learning
  3. Complexity of Optimization: Nonconvex Optimization, Equilibrium Computation, Gradient Descent Dynamics

Contact me at: alkis.kalavasis [at] yale.edu

My amazing collaborators (in roughly chronological order): Dimitris Fotakis, Christos Tzamos, Konstantinos Stavropoulos, Vasilis Kontonis, Manolis Zampetakis, Jason Milionis, Stratis Ioannidis, Eleni Psaroudaki, Grigoris Velegkas, Amin Karbasi, Hossein Esfandiari, Andreas Krause, Vahab Mirrokni, Constantine Caramanis, Shay Moran, Idan Attias, Steve Hanneke, Andreas Galanis, Anthimos Vardis Kandiros, Ioannis Anagnostides, Tuomas Sandholm, Felix Zhou, Kasper Green Larsen, Ilias Zadik, Anay Mehrotra.

Publications

Preprints
  1. Transfer Learning Beyond Bounded Density Ratios
    with Ilias Zadik and Manolis Zampetakis
Conference Publications

    2024

  1. Smaller Confidence Intervals From IPW Estimators via Data-Dependent Coarsening
    with Anay Mehrotra and Manolis Zampetakis
    COLT 2024
  2. Universal Rates for Real-Valued Regression: Separations between Cut-Off and Absolute Loss
    with Idan Attias, Steve Hanneke, Amin Karbasi and Grigoris Velegkas
    COLT 2024
  3. Replicable Learning of Large-Margin Halfspaces
    with Amin Karbasi, Kasper Green Larsen, Grigoris Velegkas and Felix Zhou
    ICML 2024
  4. On the Complexity of Computing Sparse Equilibria and Lower Bounds for No-Regret Learning in Games
    with Ioannis Anagnostides, Tuomas Sandholm and Manolis Zampetakis
    ITCS 2024
  5. Learning Hard-Constrained Models with One Sample
    with Andreas Galanis and Anthimos Vardis Kandiros
    SODA 2024
  6. 2023

  7. Optimizing Solution-Samplers for Combinatorial Problems: The Landscape of Policy-Gradient Methods
    with Constantine Caramanis, Dimitris Fotakis, Vasilis Kontonis and Christos Tzamos
    NeurIPS 2023 Selected as Oral
    [Code]
  8. Optimal Learners for Realizable Regression: PAC Learning and Online Learning
    with Idan Attias, Steve Hanneke, Amin Karbasi and Grigoris Velegkas
    NeurIPS 2023 Selected as Oral
  9. Statistical Indistinguishability of Learning Algorithms
    with Amin Karbasi, Shay Moran and Grigoris Velegkas
    ICML 2023
  10. Replicable Bandits
    with Hossein Esfandiari, Amin Karbasi, Andreas Krause, Vahab Mirrokni and Grigoris Velegkas
    ICLR 2023
  11. 2022

  12. Multiclass Learnability Beyond the PAC Framework: Universal Rates and Partial Concept Classes
    with Grigoris Velegkas and Amin Karbasi
    NeurIPS 2022
  13. Learning and Covering Sums of Independent Random Variables with Unbounded Support
    with Konstantinos Stavropoulos and Manolis Zampetakis
    NeurIPS 2022 Selected as Oral
  14. Perfect Sampling from Pairwise Comparisons
    with Dimitris Fotakis and Christos Tzamos
    NeurIPS 2022
  15. Linear Label Ranking with Bounded Noise
    with Dimitris Fotakis, Vasilis Kontonis and Christos Tzamos
    NeurIPS 2022 Selected as Oral
  16. Label Ranking through Nonparametric Regression
    with Dimitris Fotakis and Eleni Psaroudaki
    ICML 2022 Selected for Long Presentation
  17. Differentially Private Regression with Unbounded Covariates
    with Jason Milionis, Dimitris Fotakis and Stratis Ioannidis
    AISTATS 2022
  18. 2021

  19. Efficient Algorithms for Learning from Coarse Labels
    with Dimitris Fotakis, Vasilis Kontonis and Christos Tzamos
    COLT 2021
  20. Aggregating Incomplete and Noisy Rankings
    with Dimitris Fotakis and Konstantinos Stavropoulos
    AISTATS 2021
  21. 2020

  22. Efficient Parameter Estimation of Truncated Boolean Product Distributions
    with Dimitris Fotakis and Christos Tzamos
    COLT 2020
Journal Publications
  1. Efficient Parameter Estimation of Truncated Boolean Product Distributions
    with Dimitris Fotakis and Christos Tzamos
    Algorithmica

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