arXiv AI

Your Discrete Graph Diffusion Model is Secretly Memorizing

The paper investigates discrete graph diffusion models (GDMs) and demonstrates that they can memorize training data when conditioned on corrupted training graphs. By analyzing reverse diffusion trajectories on two‑block stochastic block models, the authors find that the model almost perfectly reconstructs the corrupted training graph, a phenomenon they call conditional memorization. This memorization coincides with a growing generalization gap and precedes the emergence of community structure in generated graphs, occurring across all tested node sizes.

arXiv Machine Learning
Oct 9

Beyond Sample Copying: Structural Memorization in Diffusion Models

The paper investigates why diffusion models, despite their practical success, can fully memorize training data when optimal. It shows that as training proceeds, the denoising objective causes overfitting at intermediate noise levels, creating a gap between validation and training performance. In a 2D toy model, this gap arises from the interplay between model error and the data distribution’s support density, leading to a smooth, generalizing flow field rather than exact recall of training points. The study also reveals that predictions from intermediate inference states become increasingly similar to training data in feature space, even as overall similarity to validation data remains unchanged.

By Tim Kaiser, Markus Kollmann
arXiv AI
Oct 12

When Edge Independence Fails: Joint Graph Diffusion with Latent Sociability Priors

The paper identifies a limitation of discrete graph diffusion models: independent edge updates combined with exchangeability force the terminal prior to be an Erdős–Rényi graph, which hampers denoising and leads to loss of node heterogeneity. To overcome this, the authors propose a Latent Sociability Prior (LSP) and a joint diffusion process that co‑evolves latent sociability variables with graph structure, eliminating edge independence while maintaining exchangeability. Experiments on several graph generation datasets show that this approach better captures graph distributions than baseline methods that lack node features.

By Adarsh Jamadandi, Nicolas Keriven, Aline Roumy
arXiv Machine Learning
Oct 9

Early Signatures of Memorization in Diffusion Models via Basin Geometry and Cyclic Denoising

The paper demonstrates that diffusion models encode memorization in the geometry of their learned energy landscape before it becomes visible in generated samples. By analyzing score divergence and basin volume, the authors show that localized basins form around training images early in training, and that cyclic denoising can recover these images even when one‑shot generation shows no copies. Experiments on Gaussian mixtures, CelebA, CIFAR‑10, and Stable Diffusion v1.4 confirm that basin geometry reveals memorization across various settings.

By Nikhil Verma, Siddharthan Dileep, Anoop Singh, Srikanth Sastry, Ramya Hebbalaguppe, Sayan Ranu, N. M. Anoop Krishnan
arXiv AI
Sep 25

Beyond Static Graph World Models: Learning Stochastic Latent Dynamics over Evolving Topologies

The paper introduces the Graph Dynamics Model (GDM), a world model that learns stochastic latent dynamics over evolving graph topologies. GDM employs a sparse recurrent adjacency matrix for topology updates and a recurrent state‑space architecture for stochastic transitions, enabling it to handle partially observable, stochastic environments. The authors also propose the Graph Distribution Distance (GDD) metric, using maximum mean discrepancy with a graph kernel, to compare predicted and true joint graph state distributions, and demonstrate GDM’s superior performance and zero‑shot generalisation on large graphs.

By Alex Schutz, Nick Hawes, Victor-Alexandru Darvariu
arXiv AI
Sep 10

Let It Go or Learn to Self-Correct: Continuous Diffusion for Constrained Discrete Tasks

The paper examines how Denoising Diffusion Probabilistic Models (DDPMs) perform on globally constrained discrete tasks such as Sudoku and N-queens. It shows that standard diffusion sampling, which keeps updates close to the noisy state, often preserves early mistakes, whereas sampling directly from the model’s clean predictions dramatically improves validity (e.g., Sudoku from 31% to 95%). The authors further introduce self‑correction training, exposing the model to its own predictions to reduce inference errors, which enhances the performance of standard samplers across tasks.

By Mariia Drozdova, St\'ephane Liem Nguyen, Fran\c{c}ois Fleuret