Welcome

I am a tenure-track faculty member at INSAIT, in Sofia, Bulgaria, where I lead the machine learning group.

My research interests lie in the area of trustworthy machine learning and I am especially interested in providing mathematical guarantees for machine learning models. Sample of specific topics I am currently working on are:

Making collaborative learning methods, such as federated learning, more robust and reliable.
Studying topics at the intersection of machine learning and game theory, in particular incentives for data sharing.
Understanding the impact of machine learning on society, in particular by analysing the fairness and long-term impact of machine learning models.

Before INSAIT I was a postdoctoral fellow at the ETH AI Center, working under the supervision of Prof. Martin Vechev and Prof. Fanny Yang. Prior to that I was a PhD student at IST Austria, working in the group of Prof. Christoph Lampert. I was also part of the ELLIS PhD Program.

Supervision: At INSAIT, I have the pleasure of working with Nikita Tsoy (joint with Martin Jaggi), Ivan Kirev (joint with Andreas Krause), Kristian Minchev, Kostadin Garov (joint with Martin Vechev).

Links: Google Scholar profile, LinkedIn, a full CV .

Papers

The order of the authors is by contribution, unless specified otherwise.

Nikita Tsoy, Nikola Konstantinov
Simplicity Bias of Two-Layer Networks beyond Linearly Separable Data
In: International Conference on Machine Learning (ICML) , 2024

Nikita Tsoy, Anna Mihalkova, Teodora Todorova, Nikola Konstantinov
Provable Mutual Benefits from Federated Learning in Privacy-Sensitive Domains
In: International Conference on Artificial Intelligence and Statistics (AISTATS) , 2024

Nikita Tsoy, Nikola Konstantinov
Strategic Data Sharing between Competitors
In: Conference on Neural Information Processing Systems (NeurIPS) , 2023

Florian E. Dorner, Nikola Konstantinov, Giorgi Pashaliev, Martin Vechev
Incentivizing Honesty among Competitors in Collaborative Learning and Optimization
In: Conference on Neural Information Processing Systems (NeurIPS) , 2023

Florian E. Dorner, Momchil Peychev, Nikola Konstantinov, Naman Goel, Elliott Ash, Martin Vechev
Human-Guided Fair Classification for Natural Language Processing
In: International Conference on Learning Representations (ICLR), Spotlight , 2023
Short version presented in: TSRML@NeurIPS , 2022

Dimitar I. Dimitrov, Mislav Balunović, Nikola Konstantinov, Martin Vechev
Data Leakage in Federated Averaging
To appear in: Transactions of Machine Learning Research (TMLR) , 2022

Eugenia Iofinova*, Nikola Konstantinov*, Christoph H. Lampert
FLEA: Provably Fair Multisource Learning from Unreliable Training Data
To appear in: Transactions of Machine Learning Research (TMLR) , 2022
* Denotes equal contribution

Nikola Konstantinov, Christoph H. Lampert
Fairness-Aware PAC Learning from Corrupted Data
In: Journal of Machine Learning Research (JMLR) , 2022

Nikola Konstantinov, Christoph H. Lampert
On the Impossibility of Fairness-Aware Learning from Corrupted Data
Contributed talk + in proceedings of AFCR@NeurIPS , 2021

Nikola Konstantinov, Elias Frantar, Dan Alistarh, Christoph H. Lampert
On the Sample Complexity of Adversarial Multi-Source PAC Learning
In: International Conference on Machine Learning (ICML), 2020

Nikola Konstantinov, Christoph H. Lampert
Robust Learning from Untrusted Sources
In: International Conference on Machine Learning (ICML), 2019; Long Talk

Dan Alistarh, Torsten Hoefler, Mikael Johansson, Nikola Konstantinov*, Sarit Khirirat, Cedric Renggli
The Convergence of Sparsified Gradient Methods
In: Conference on Neural Information Processing Systems (NeurIPS) , 2018
* Authors' order is alphabetical.

Dan Alistarh, Chris De Sa, Nikola Konstantinov*
The Convergence of Stochastic Gradient Descent in Asynchronous Shared Memory
In: ACM Symposium of Principles of Distributed Computing (PODC) , 2018
* Authors' order is alphabetical.