Konstantinos Stavropoulos

Konstantinos Stavropoulos (Kostas)

Ph.D. Student

University of Texas at Austin

[email protected]

About me

I am a final-year Ph.D. candidate in Computer Science at UT Austin. I am fortunate to be advised by Prof. Adam Klivans. Before that, I studied Electrical and Computer Engineering at the National Technical University of Athens, where I worked with Prof. Dimitris Fotakis. I am grateful to be supported by the 2025 Apple Scholars in AI/ML Fellowship. In summer 2025, I was a research intern at Apple MLR, working with Parikshit Gopalan and Kunal Talwar.

My research focuses on the computational foundations of reliability in machine learning. I am particularly interested in designing efficient learning algorithms with provable guarantees that do not rely on strong distributional or modeling assumptions, especially in challenging scenarios like learning under distribution shift or data contamination.

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News

Fall 2026I will join the School of Mathematics at the Institute for Advanced Study as a Postdoctoral Member.
June 29, 2026I am co-organizing a tutorial on Computational Foundations of Reliable Learning at COLT 2026, with Adam Klivans and Arsen Vasilyan.
June 2026Our joint work received the Best Paper Award at the Symposium on Foundations of Responsible Computing (FORC) 2026.
December 2025Our joint work received the Best Paper Award at the Reliable ML Workshop at NeurIPS 2025.

Publications

Following the convention in theoretical computer science, authors are listed in alphabetical order.

Learning with Distribution Shift

Classical learning formulations assume train and test data come from the same distribution, which rarely holds in practice. I design efficient algorithms that provably succeed under distribution shift, including tolerant and testable guarantees that certify when their output can be trusted.

Selected papers (7)
Gautam Chandrasekaran, Georgios Gkrinias, Adam Klivans, Konstantinos Stavropoulos, Arsen Vasilyan
Preprint
Adam Klivans, Shyamal Patel, Konstantinos Stavropoulos, Arsen Vasilyan
COLT 2026
Gautam Chandrasekaran, Adam Klivans, Lin Lin Lee, Konstantinos Stavropoulos
ICLR 2025
Surbhi Goel, Abhishek Shetty, Konstantinos Stavropoulos, Arsen Vasilyan
NeurIPS 2024
Spotlight · NeurIPS 2024
Gautam Chandrasekaran, Adam Klivans, Vasilis Kontonis, Konstantinos Stavropoulos, Arsen Vasilyan
NeurIPS 2024
Adam Klivans, Konstantinos Stavropoulos, Arsen Vasilyan
COLT 2024

Learning from Noisy or Corrupted Data

Training datasets are often contaminated by naturally occurring or adversarial corruptions. I develop efficient algorithms that learn with provable guarantees under challenging noise models, ranging from Massart noise and adversarial label noise to nasty noise and heavy additive contamination.

Selected papers (4)
Gautam Chandrasekaran, Adam Klivans, Konstantinos Stavropoulos, Arsen Vasilyan
STOC 2026
Adam Klivans, Konstantinos Stavropoulos, Kevin Tian, Arsen Vasilyan
NeurIPS 2025
Spotlight · NeurIPS 2025
Adam Klivans, Konstantinos Stavropoulos, Arsen Vasilyan
COLT 2025
Gautam Chandrasekaran, Vasilis Kontonis, Konstantinos Stavropoulos, Kevin Tian
NeurIPS 2024
Spotlight · NeurIPS 2024

Testable Learning

The testable learning framework asks an algorithm to verify, rather than assume, that its distributional assumptions hold. I build efficient tester-learners that either return a classifier with a certificate of near-optimality or reject the data.

Selected papers (3)
Surbhi Goel, Adam Klivans, Konstantinos Stavropoulos, Arsen Vasilyan
COLT 2026
Best Paper Award · Reliable ML Workshop @ NeurIPS 2025
Aravind Gollakota, Adam Klivans, Konstantinos Stavropoulos, Arsen Vasilyan
ICLR 2024
Aravind Gollakota, Adam Klivans, Konstantinos Stavropoulos, Arsen Vasilyan
NeurIPS 2023
Oral · NeurIPS 2023 (top 0.54%)

Beyond Worst-Case Models

Worst-case analysis can be overly pessimistic about what is learnable. I use beyond-worst-case lenses, such as smoothed or average-case analysis, to explain why learning remains tractable on realistic, mildly perturbed instances.

Selected papers (2)
Gautam Chandrasekaran, Raghu Meka, Konstantinos Stavropoulos
STOC 2026
Gautam Chandrasekaran, Adam Klivans, Vasilis Kontonis, Raghu Meka, Konstantinos Stavropoulos
COLT 2024
Best Paper Award · COLT 2024

Calibration and Real-Valued Prediction

Beyond binary classification, reliable predictions require well-calibrated probabilities and accurate real-valued outputs. I study how to verify or achieve such properties efficiently, with applications to decision making and omniprediction.

Selected papers (2)
Parikshit Gopalan, Konstantinos Stavropoulos, Kunal Talwar, Pranay Tankala
STOC 2026
Parikshit Gopalan, Konstantinos Stavropoulos, Kunal Talwar, Pranay Tankala
FORC 2026
Best Paper Award · FORC 2026

Awards & Honors

Best Paper Award at the Symposium on the Foundations of Responsible Computing (FORC)
2026
Awarded for joint work on The Importance of Being Smoothly Calibrated.
Best Paper Award at Reliable ML Workshop @ NeurIPS
2025
Awarded for joint work on Testing Noise Assumptions of Learning Algorithms.
Selected as an Apple Scholar in AI/ML.
Best Paper Award at the Conference on Learning Theory (COLT)
2024
Awarded for joint work on Smoothed Analysis for Learning Concepts with Low Intrinsic Dimension.
Bodossaki & Leventis Scholarships
2022 – 2025
My Ph.D. studies were generously supported by scholarships from the Bodossaki and Leventis foundations.
Awarded by the State Scholarships Foundation of Greece for ranking first among students in my cohort who completed the ECE degree at NTUA within the nominal period of studies.

Service

Computational Foundations of Reliable Learning
2026
Tutorial at the Conference on Learning Theory (COLT), co-organized with Adam Klivans and Arsen Vasilyan.
Reviewing & Subreviewing
COLT (2025, 2026), FOCS (2025, 2026), STOC 2026, ITCS 2026, NeurIPS (2023, 2026), ICLR 2024, ICML 2024, RANDOM 2026