Higher-Order Molecular Learning: The Cellular Transformer

We present the Cellular Transformer (CT), a novel topological deep learning (TDL) framework that extends graph transformers to regular cell complexes (CCs), enabling improved modeling of higher-order molecular structures. Representing complex biomolecules effectively is a notorious challenge due to the delicate interplay between geometry (the physical conformation of molecules) and topology (their connectivity and higher-order relationships). Traditional graph-based models often struggle with these complexities, either ignoring higher-order topological features or addressing them in ad-hoc ways. In this work, we introduce a principled cellular transformer mechanism that natively incorporates topological cues (e.g., higher-order bonds, loops, and fused rings). To complement this, we propose the notion of augmented molecular cell complex, a novel and richer representation of molecules able to leverage ring-level motifs and features. Our evaluations on the MoleculeNet benchmark and graph datasets lifted into CCs reveal consistent performance gains over GNN- and transformer-based architectures. Notably, our approach achieves these without relying on graph rewiring, virtual nodes, or in-domain structural encodings, indicating the power of topologically informed attention to capture subtle, global interactions vital to drug discovery and molecular property prediction.