TDGNet: Hallucination Detection in Diffusion Language Models via Temporal Dynamic Graphs

Arshia Hemmat, Philip Torr, Yongqiang Chen, Junchi Yu


Abstract
Diffusion language models (D-LLMs) offer parallel denoising and bidirectional context, but hallucination detection for D-LLMs remains underexplored. Prior detectors developed for auto-regressive LLMs typically rely on single-pass cues and do not directly transfer to diffusion generation, where factuality evidence is distributed across the denoising trajectory and may appear, drift, or be self-corrected over time. We introduce TDGNet, a temporal dynamic graph framework that formulates hallucination detection as learning over evolving token-level attention graphs. At each denoising step, we sparsify the attention graph and update per-token memories via message passing, then apply temporal attention to aggregate trajectory-wide evidence for final prediction. Experiments across four D-LLMs spanning dense and Mixture-of-Experts architectures (7B—16B parameters) and multiple diffusion paradigms show consistent AUROC improvements over output-based, latent-based, and static-graph baselines, with single-pass inference and modest overhead. These results highlight the importance of temporal reasoning on attention graphs for robust hallucination detection in diffusion language models.
Anthology ID:
2026.emnlp-main.2479
Volume:
Proceedings of the 2026 Conference on Empirical Methods in Natural Language Processing
Month:
October
Year:
2026
Address:
Budapest, Hungary
Editors:
Hung-Yi Lee, Sunipa Dev, Jessy Li, Desmond Elliott
Venue:
EMNLP
SIG:
SIGDAT
Publisher:
Association for Computational Linguistics
Note:
Pages:
56277–56301
Language:
URL:
https://aclanthology.org/2026.emnlp-main.2479/
DOI:
Bibkey:
Cite (ACL):
Arshia Hemmat, Philip Torr, Yongqiang Chen, and Junchi Yu. 2026. TDGNet: Hallucination Detection in Diffusion Language Models via Temporal Dynamic Graphs. In Proceedings of the 2026 Conference on Empirical Methods in Natural Language Processing, pages 56277–56301, Budapest, Hungary. Association for Computational Linguistics.
Cite (Informal):
TDGNet: Hallucination Detection in Diffusion Language Models via Temporal Dynamic Graphs (Hemmat et al., EMNLP 2026)
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PDF:
https://aclanthology.org/2026.emnlp-main.2479.pdf