Floris Geerts
Floris Geerts is a researcher whose work connects database theory with graph neural networks. He earned a master's degree in Mathematics at Ghent in 1995 and a doctorate in Computer Science at Hasselt in 2001, then joined the University of Antwerp as Research Professor in 2011 after research posts in Helsinki and Edinburgh. In 2015, he shared the ACM PODS Mendelzon Test-of-Time Award, and in 2022 he and Juan Reutter received an ICLR Outstanding Paper Award for GNN expressivity. His papers characterized GNNs with local graph parameters in 2021, examined links between expressivity and generalization in 2024 and 2025, and studied algorithm learning in 2026. As of October 2026, he is a professor in Antwerp's Department of Computer Science and guides Adrem Data Lab research on data management and graph learning.
- Now at
- University of Antwerp
Timeline
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1995–2011
From Ghent degrees to Antwerp
At the University of Ghent, he earns an M.Sc. in Mathematics in 1995; at the University of Hasselt, he earns a Ph.D. in Computer Science in 2001. He takes a postdoctoral post at the University of Helsinki and spends seven years as a Senior Research Fellow at the University of Edinburgh before joining the University of Antwerp as Research Professor in 2011.
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2015
A PODS test-of-time award
He shares the 2015 ACM PODS Alberto O. Mendelzon Test-of-Time Award with Michael Benedikt and Wenfei Fan for 'XPath satisfiability in the presence of DTDs,' published in the PODS proceedings in 2005.
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2021
Local graph parameters for GNNs
In 2021, he coauthors 'Graph Neural Networks with Local Graph Parameters' with Pablo Barceló, Juan Reutter and Maksimilian Ryschkov. The paper characterizes the distinguishing power of these GNNs using a variant of the Weisfeiler–Leman test and graph structural properties.
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2022
An ICLR Outstanding Paper Award
He and Juan L. Reutter receive an ICLR 2022 Outstanding Paper Award for 'Expressiveness and Approximation Properties of Graph Neural Networks.' The paper views GNNs as expressions in a tensor language and derives bounds on their separation power using Weisfeiler–Leman tests.
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2023
Simons visit and Karp lecture
He is a visiting scientist in Fall 2023 in the Simons Institute program Logic and Algorithms in Database Theory and AI. In 2023, he gives the Richard M. Karp Distinguished Lecture 'The Power of Graph Learning,' using connections between graph learning and database theory to analyze the expressive power of graph learning methods.
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2024
Expressivity and generalization
In 2024, he coauthors 'Weisfeiler-Leman at the margin: When more expressivity matters' with Billy J. Franks, Christopher Morris and Ameya Velingker. The paper finds that a GNN architecture's expressivity offers limited insight into generalization performance when viewed through graph isomorphism. In August 2024, he gives an Oxford seminar titled 'Expressiveness and Generalisation in Graph Neural Networks.'
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2025
GNN generalization theory at ICLR
In 2025, he coauthors 'Towards Bridging Generalization and Expressivity of Graph Neural Networks' with Shouheng Li, Dongwoo Kim and Qing Wang for ICLR. The paper connects GNN generalization to the variance in graph structures they capture and proposes a margin-based generalization bound.
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As of October 2026
Professor in Antwerp
As of October 2026, he is a professor in the University of Antwerp's Department of Computer Science and part of Adrem Data Lab, where he guides research on the principles of data management and graph learning. In 2026, he coauthors 'Which Algorithms Can Graph Neural Networks Learn?' for ICML, which gives conditions for message-passing GNNs to learn tasks such as single-source shortest paths and minimum spanning trees.
Career
- Since 2011University of AntwerpResearch Professor
- 2023University of California, BerkeleyVisiting Scientist
- Until 2011University of EdinburghSenior Research Fellow
Education
- 2001Hasselt UniversityPh.D. in Computer Science
- 1995Ghent UniversityM.Sc. in Mathematics
Sources and credits
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- Floris Geerts
- Michael Benedikt wins ACM PODS Alberto O. Mendelzon Test-of-Time Award
- Floris Geerts
- [2106.06707] Graph Neural Networks with Local Graph Parameters
- Announcing the ICLR 2022 Outstanding Paper Award Recipients – ICLR Blog
- [2204.04661] Expressiveness and Approximation Properties of Graph Neural Networks
- The Power of Graph Learning | Richard M. Karp Distinguished Lecture
- [2402.07568] Weisfeiler-Leman at the margin: When more expressivity matters
- Expressiveness and Generalisation in Graph Neural Networks
- Towards Bridging Generalization and Expressivity of Graph Neural Networks
- Which Algorithms Can Graph Neural Networks Learn?


