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Cristian Bodnar

8 accepted papers

2023

On the Expressive Power of Geometric Graph Neural Networks

ICML 2023poster

The expressive power of Graph Neural Networks (GNNs) has been studied extensively through the Weisfeiler-Leman (WL) graph isomorphism test. However, standard GNNs and the WL framework are inapplicable for geometric graphs embedded in Euclidean space, such as biomolecules, materials, and other physic…

2022

Neural Sheaf Diffusion: A Topological Perspective on Heterophily and Oversmoothing in GNNs

NeurIPS 2022accept

Cellular sheaves equip graphs with a ``geometrical'' structure by assigning vector spaces and linear maps to nodes and edges. Graph Neural Networks (GNNs) implicitly assume a graph with a trivial underlying sheaf. This choice is reflected in the structure of the graph Laplacian operator, the propert…

2021

A Metric Space Perspective on Self-Supervised Policy Adaptation

RA-L 2021

One of the most challenging aspects of real-world reinforcement learning (RL) is the multitude of unpredictable and ever-changing distractions that could divert an agent from what was tasked to do in its training environment. While an agent could learn from reward signals to ignore them, the complex

Cited by 0SourceScholar
2021

Weisfeiler and Lehman Go Cellular: CW Networks

NeurIPS 2021poster

Graph Neural Networks (GNNs) are limited in their expressive power, struggle with long-range interactions and lack a principled way to model higher-order structures. These problems can be attributed to the strong coupling between the computational graph and the input graph structure. The recently pr…

2021

Weisfeiler and Lehman Go Topological: Message Passing Simplicial Networks

ICML 2021spotlight

The pairwise interaction paradigm of graph machine learning has predominantly governed the modelling of relational systems. However, graphs alone cannot capture the multi-level interactions present in many complex systems and the expressive power of such schemes was proven to be limited. To overcome…

2020

On Second Order Behaviour in Augmented Neural ODEs

NeurIPS 2020poster

Neural Ordinary Differential Equations (NODEs) are a new class of models that transform data continuously through infinite-depth architectures. The continuous nature of NODEs has made them particularly suitable for learning the dynamics of complex physical systems. While previous work has mostly bee…

Cited by 116SourcePDFScholar
2020

Quantile QT-Opt for Risk-Aware Vision-Based Robotic Grasping

RSS 2020poster

The distributional perspective on reinforcement learning (RL) has given rise to a series of successful Q-learning algorithms, resulting in state-of-the-art performance in arcade game environments. However, it has not yet been analyzed how these findings from a discrete setting translate to complex p…

Cited by 65SourcePDFScholar