Scoped Semantic Invariance as a Foundation for LLM Reliability

Rosario Uceda-Sosa, Maria Chang, Karthikeyan Natesan Ramamurthy, Moninder Singh


Abstract
LLMs often answer semantically equivalent queries inconsistently, even when the underlying facts are known. We formalize consistency as semantic invariance over equivalence classes of queries and show that invariance under arbitrary meaning-preserving transformations is undecidable in general. This motivates scoped semantic invariance, where model behavior is evaluated relative to bounded semantic domains.

We operationalize this framework using knowledge graphs (KGs), which act as explicit semantic control structures defining local semantics and grounding contexts. Across the MITRE D3FEND ontology and eight Wikidata-derived domains, we show that inconsistencies are structured rather than random, concentrating in localized hotspot subgraphs organized around recurring TREE, STAR, and CYCLE patterns that recur across models and domains.

We further show that selective graph grounding improves consistency with the KG specification and cross-model agreement, while indiscriminate grounding introduces regressions. A layered grounding strategy achieves the strongest monotonicity profile, preserving KG-consistent knowledge while reducing inconsistency. Finally, we show that hotspot structures discovered from simple consistency probes transfer to more realistic compositional reasoning tasks, positioning them as a practical reliability layer for predicting and targeting failures rather than a canonical decomposition.
Anthology ID:
2026.emnlp-main.2545
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:
57863–57884
Language:
URL:
https://aclanthology.org/2026.emnlp-main.2545/
DOI:
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Cite (ACL):
Rosario Uceda-Sosa, Maria Chang, Karthikeyan Natesan Ramamurthy, and Moninder Singh. 2026. Scoped Semantic Invariance as a Foundation for LLM Reliability. In Proceedings of the 2026 Conference on Empirical Methods in Natural Language Processing, pages 57863–57884, Budapest, Hungary. Association for Computational Linguistics.
Cite (Informal):
Scoped Semantic Invariance as a Foundation for LLM Reliability (Uceda-Sosa et al., EMNLP 2026)
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PDF:
https://aclanthology.org/2026.emnlp-main.2545.pdf