Building Long-Term LLM Memory with Neo-Davidsonian Discourse Units

Sizhe Zhou, Yanzhen Shen, Siru Ouyang, Yuyang Bai, Yiheng Shu, Yu Zhang, Jiawei Han


Abstract
Long-horizon conversational agents need persistent memory beyond a fixed context window, yet memory effectiveness depends on the units stored and retrieved. Existing systems either discard fine-grained details during compression, retrieve units that are too coarse or context-poor, or fragment discourse into entity-relation triples. We propose Neo-Davidsonian Discourse Units: enriched Elementary Discourse Units (EDUs) that each express one event or fact with normalized entities, temporal grounding, and enough context to stand alone. The resulting units are non-lossy at the session level, atomic for retrieval, and naturally expose event arguments for graph-based associative recall. We instantiate this representation in EMem, which retrieves EDUs with dense representations and relevance filtering based on large language models, and EMem-G, which further organizes sessions, EDUs, and arguments in an event graph and applies Personalized PageRank. On LoCoMo and LongMemEvalS benchmarks, our methods improve over prior state-of-the-art by up to 21.3% while using up to 7× shorter effective context.
Anthology ID:
2026.findings-emnlp.924
Volume:
Findings of the Association for Computational Linguistics: EMNLP 2026
Month:
October
Year:
2026
Address:
Budapest, Hungary
Editors:
Hung-Yi Lee, Sunipa Dev, Jessy Li, Desmond Elliott
Venue:
Findings
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SIGDAT
Publisher:
Association for Computational Linguistics
Note:
Pages:
19494–19531
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URL:
https://aclanthology.org/2026.findings-emnlp.924/
DOI:
Bibkey:
Cite (ACL):
Sizhe Zhou, Yanzhen Shen, Siru Ouyang, Yuyang Bai, Yiheng Shu, Yu Zhang, and Jiawei Han. 2026. Building Long-Term LLM Memory with Neo-Davidsonian Discourse Units. In Findings of the Association for Computational Linguistics: EMNLP 2026, pages 19494–19531, Budapest, Hungary. Association for Computational Linguistics.
Cite (Informal):
Building Long-Term LLM Memory with Neo-Davidsonian Discourse Units (Zhou et al., Findings 2026)
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PDF:
https://aclanthology.org/2026.findings-emnlp.924.pdf