activity
20152026
most citedComparing Graph Spectra of Adjacency and Laplacian Matrices

4 citations · 22 across the 28 of their papers we have counts for

collaborators

28 papers

cs.CV2026

Pulmonary Embolism Risk Stratification from CTPA and Medical Records: Vascular Graphs Are Not All You Need

Nathan Painchaud, Tristan Habémont, Morgane des Ligneris +6

Risk stratification for pulmonary embolism (PE) is critical for clinical decision-making. Stratification guidelines are based on patient medical records, parameters measured from c…

cs.LG2026

GraViti: Graph-Level Variational Autoencoders with Relaxed Permutation Invariance

Roman Bresson, Konstantinos Divriotis, Johannes F. Lutzeyer +2

We introduce GraViti, a transformer-based graph-level variational autoencoder that encodes entire graphs into single, fixed-dimensional latent vectors rather than per-node embeddin…

cs.LG2025

If You Want to Be Robust, Be Wary of Initialization

Sofiane Ennadir, Johannes F. Lutzeyer, Michalis Vazirgiannis +1

Graph Neural Networks (GNNs) have demonstrated remarkable performance across a spectrum of graph-related tasks, however concerns persist regarding their vulnerability to adversaria…

cs.LG2025

Enhancing Graph Classification Robustness with Singular Pooling

Sofiane Ennadir, Oleg Smirnov, Yassine Abbahaddou +2

Graph Neural Networks (GNNs) have achieved strong performance across a range of graph representation learning tasks, yet their adversarial robustness in graph classification remain…

cs.LG2025

SHAKE-GNN: Scalable Hierarchical Kirchhoff-Forest Graph Neural Network

Zhipu Cui, Johannes Lutzeyer

Graph Neural Networks (GNNs) have achieved remarkable success across a range of learning tasks. However, scaling GNNs to large graphs remains a significant challenge, especially fo…

cs.LG2025

ADMP-GNN: Adaptive Depth Message Passing GNN

Yassine Abbahaddou, Fragkiskos D. Malliaros, Johannes F. Lutzeyer +1

Graph Neural Networks (GNNs) have proven to be highly effective in various graph learning tasks. A key characteristic of GNNs is their use of a fixed number of message-passing step…

cs.LG2025

Graph Representational Learning: When Does More Expressivity Hurt Generalization?

Sohir Maskey, Raffaele Paolino, Fabian Jogl +2

Graph Neural Networks (GNNs) are powerful tools for learning on structured data, yet the relationship between their expressivity and predictive performance remains unclear. We intr…

q-bio.QM2025

Efficient Data Selection for Training Genomic Perturbation Models

George Panagopoulos, Johannes F. Lutzeyer, Sofiane Ennadir +2

Genomic studies face a vast hypothesis space, while interventions such as gene perturbations remain costly and time-consuming. To accelerate such experiments, gene perturbation mod…

cs.LG2024

Post-Hoc Robustness Enhancement in Graph Neural Networks with Conditional Random Fields

Yassine Abbahaddou, Sofiane Ennadir, Johannes F. Lutzeyer +2

Graph Neural Networks (GNNs), which are nowadays the benchmark approach in graph representation learning, have been shown to be vulnerable to adversarial attacks, raising concerns…

cs.LG2024

Centrality Graph Shift Operators for Graph Neural Networks

Yassine Abbahaddou, Fragkiskos D. Malliaros, Johannes F. Lutzeyer +1

Graph Shift Operators (GSOs), such as the adjacency and graph Laplacian matrices, play a fundamental role in graph theory and graph representation learning. Traditional GSOs are ty…

cs.LG2024★ 1 cited

Graph Neural Network Generalization with Gaussian Mixture Model Based Augmentation

Yassine Abbahaddou, Fragkiskos D. Malliaros, Johannes F. Lutzeyer +2

Graph Neural Networks (GNNs) have shown great promise in tasks like node and graph classification, but they often struggle to generalize, particularly to unseen or out-of-distribut…

cs.LG2024★ 1 cited

Graph Neural Networks on Discriminative Graphs of Words

Yassine Abbahaddou, Johannes F. Lutzeyer, Michalis Vazirgiannis

In light of the recent success of Graph Neural Networks (GNNs) and their ability to perform inference on complex data structures, many studies apply GNNs to the task of text classi…

cs.LG2024★ 1 cited

Understanding Virtual Nodes: Oversquashing and Node Heterogeneity

Joshua Southern, Francesco Di Giovanni, Michael Bronstein +1

While message passing neural networks (MPNNs) have convincing success in a range of applications, they exhibit limitations such as the oversquashing problem and their inability to…

cs.LG2024★ 2 cited

Bounding the Expected Robustness of Graph Neural Networks Subject to Node Feature Attacks

Yassine Abbahaddou, Sofiane Ennadir, Johannes F. Lutzeyer +2

Graph Neural Networks (GNNs) have demonstrated state-of-the-art performance in various graph representation learning tasks. Recently, studies revealed their vulnerability to advers…

cs.LG2024

A Simple and Yet Fairly Effective Defense for Graph Neural Networks

Sofiane Ennadir, Yassine Abbahaddou, Johannes F. Lutzeyer +2

Graph Neural Networks (GNNs) have emerged as the dominant approach for machine learning on graph-structured data. However, concerns have arisen regarding the vulnerability of GNNs…

stat.ML2024★ 2 cited

Graph Neural Machine: A New Model for Learning with Tabular Data

Giannis Nikolentzos, Siyun Wang, Johannes Lutzeyer +1

In recent years, there has been a growing interest in mapping data from different domains to graph structures. Among others, neural network models such as the multi-layer perceptro…

cs.LG2023★ 4 cited

Path Neural Networks: Expressive and Accurate Graph Neural Networks

Gaspard Michel, Giannis Nikolentzos, Johannes Lutzeyer +1

Graph neural networks (GNNs) have recently become the standard approach for learning with graph-structured data. Prior work has shed light into their potential, but also their limi…

cs.LG2022

New Frontiers in Graph Autoencoders: Joint Community Detection and Link Prediction

Guillaume Salha-Galvan, Johannes F. Lutzeyer, George Dasoulas +2

Graph autoencoders (GAE) and variational graph autoencoders (VGAE) emerged as powerful methods for link prediction (LP). Their performances are less impressive on community detecti…

cs.LG2022

Improving Graph Neural Networks at Scale: Combining Approximate PageRank and CoreRank

Ariel R. Ramos Vela, Johannes F. Lutzeyer, Anastasios Giovanidis +1

Graph Neural Networks (GNNs) have achieved great successes in many learning tasks performed on graph structures. Nonetheless, to propagate information GNNs rely on a message passin…

cs.LG2022

Graph Ordering Attention Networks

Michail Chatzianastasis, Johannes F. Lutzeyer, George Dasoulas +1

Graph Neural Networks (GNNs) have been successfully used in many problems involving graph-structured data, achieving state-of-the-art performance. GNNs typically employ a message-p…

cs.LG2022★ 1 cited

Modularity-Aware Graph Autoencoders for Joint Community Detection and Link Prediction

Guillaume Salha-Galvan, Johannes F. Lutzeyer, George Dasoulas +2

Graph autoencoders (GAE) and variational graph autoencoders (VGAE) emerged as powerful methods for link prediction. Their performances are less impressive on community detection pr…

cs.LG2021★ 1 cited

Node Feature Kernels Increase Graph Convolutional Network Robustness

Mohamed El Amine Seddik, Changmin Wu, Johannes F. Lutzeyer +1

The robustness of the much-used Graph Convolutional Networks (GCNs) to perturbations of their input is becoming a topic of increasing importance. In this paper, the random GCN is i…

cs.LG2021★ 2 cited

Sparsifying the Update Step in Graph Neural Networks

Johannes F. Lutzeyer, Changmin Wu, Michalis Vazirgiannis

Message-Passing Neural Networks (MPNNs), the most prominent Graph Neural Network (GNN) framework, celebrate much success in the analysis of graph-structured data. Concurrently, the…

cs.LG2021★ 1 cited

Learning Parametrised Graph Shift Operators

George Dasoulas, Johannes Lutzeyer, Michalis Vazirgiannis

In many domains data is currently represented as graphs and therefore, the graph representation of this data becomes increasingly important in machine learning. Network data is, im…