Giannis Nikolentzos

Assistant Professor Department of Informatics and Telecommunications, University of Peloponnese, Terma Karaiskaki, Tripoli 22131, Greece. E-mail: lastname [at] uop [DOT] gr

About me

I am an Assistant Professor at the Department of Informatics and Telecommunications of the University of Peloponnese. My research interests lie mostly in the field of graph representation learning and learning on structured data. Before joining the University of Peloponnese, I was a postdoctoral researcher at Ecole Polytechnique. I obtained my PhD in computer science from the Athens University of Economics and Business, where I was advised by Professor Michalis Vazirgiannis. During my PhD, my research was generously supported by a Scholarship from the Academy of Athens. Before that, I obtained an MSc in Artificial Intelligence from the University of Southampton and a Diploma in Electrical and Computer Engineering from the University of Patras.

A brief cv.

Research

My research interests include

• Learning on Graphs

• Graph Mining

• Machine Learning

• Artificial Intelligence

Recent Publications

1. G. Nikolentzos, D. Kelesis and M. Vazirgiannis, "On the theoretical expressive power of graph transformers for solving graph problems", Neural Networks, Volume 194, (2025). [pdf]

2. R. Bresson, G. Nikolentzos, G. Panagopoulos, M. Chatzianastasis, J. Pang, and M. Vazirgiannis, "KAGNNs: Kolmogorov-Arnold Networks meet Graph Learning", Transactions on Machine Learning Research, (2025). [pdf]

3. N. Nakis, C. Kosma, G. Nikolentzos, M. Chatzianastasis, I. Evdaimon, and M. Vazirgiannis, "Signed Graph Autoencoder for Explainable and Polarization-Aware Network Embeddings", In Proceedings of the 28th International Conference on Artificial Intelligence and Statistics, pp. 496-504, 2025.

4. G. Michel, G. Nikolentzos, J. Lutzeyer, and M. Vazirgiannis, "Path Neural Networks: Expressive and Accurate Graph Neural Networks", In Proceedings of the 40th International Conference on Machine Learning, pp. 24737-24755, 2023. [pdf]

5. G. Nikolentzos, M. Vazirgiannis, C. Xypolopoulos, M. Lingman, and E.G. Brandt, "Synthetic electronic health records generated with variational graph autoencoders", npj Digital Medicine, Volume 6, No. 1, (2023).

6. G. Nikolentzos and M. Vazirgiannis, "Geometric Random Walk Graph Neural Networks via Implicit Layers", In Proceedings of the 26th International Conference on Artificial Intelligence and Statistics, pp. 2035-2053, 2023. [pdf] [code]

Preprints

1. G. Nikolentzos and K. Skianis, "On the Lipschitz Continuity of Set Aggregation Functions and Neural Networks for Sets", 2025. [pdf]