Andreas Theophilou

dblp:438/7562 · DBLP profile ↗
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1ranked-venue papers
1as first author
1since 2021 · last 2025
—ORCID · none

Domains — the database's venue-derived domains; a paper can count in several

Artificial intelligence and machine learning · 1 · 1 first-author · 1 since 2021

Expertise — from the expertise taxonomy: the topics of the expert's papers under the CCF categories. A weight counts papers with recency: 1 for a paper about the topic, 0.3 when the topic is its context, halved every five years.

Artificial intelligence
1 paper
Reinforcement learning · 54% Graph learning · 46%

Topics — the 4 heaviest of 5, each with the papers that count most for it

TopicWeightPapersLastEvidence papers
Machine learning › Reinforcement learning
exploration
0.912025
Novel Exploration via Orthogonality · NeurIPS 2025
Machine learning › Graph learning › spectral graph theory
graph laplacian
0.912025
Novel Exploration via Orthogonality · NeurIPS 2025
Machine learning › Reinforcement learning › exploration
novelty-based exploration
0.912025
Novel Exploration via Orthogonality · NeurIPS 2025
Machine learning › Graph learning
spectral graph methods
0.912025
Novel Exploration via Orthogonality · NeurIPS 2025

Methods — techniques the papers use, named apart from their topics

laplacian eigenvectors · 0.9gradient flow · 0.9
YearPublicationVenuePosition
2025 Novel Exploration via Orthogonality
abstract
Efficient exploration remains one of the most important open problems in reinforcement learning. Discovering novel states or transitions requires policies that efficiently direct the agent away from the regions of the state space that are already well explored. We introduce Novel Exploration via Orthogonality (NEO), an approach that automatically uncovers not only which regions of the environment are novel but also how to reach them by leveraging Laplacian representations. NEO uses the eigenvectors of a modified graph Laplacian to induce gradient flows from states that are frequently visited (less novel) to states that are seldom visited (more novel). We show that NEO's modified Laplacian yields eigenvectors whose extreme values align with the most novel regions of the state space. We provide bounds for the eigenvalues of the modified Laplacian; and we show that the smoothest eigenvectors with real eigenvalues below certain thresholds provide guaranteed gradients to novel states for both undirected and directed graphs. In an empirical evaluation in online, incremental settings, NEO outperformed related state-of-the-art approaches, including eigen-options and cover options, in a large collection of undirected and directed environments with varying connectivity structures.
Andreas Theophilou, Özgür Simsek
NeurIPS1