Iterative Natural Logic Verification for Multi-hop Question Answering

Jihao Shi, Liang Yang, Hongfei Lin


Abstract
Multi-hop question answering requires composing multiple pieces of evidence to derive the correct answer, making it particularly vulnerable to hallucinated intermediate reasoning steps. A common failure mode arises when neural generators produce intermediate sentences that are fluent but logically inconsistent with the underlying facts, which can subsequently mislead downstream reasoning. In this paper, we propose ITERLOGIC, an iterative natural logic verification framework for multi-hop question answering, which explicitly integrates symbolic verification into the generation process. Specifically, a neural generator composes candidate intermediate sentences from retrieved facts, while a natural logic verifier evaluates their logical consistency with the source evidence. Low-scoring candidates are iteratively rejected and regenerated, allowing the system to progressively eliminate hallucinated compositions. This lightweight interaction upgrades natural logic from a passive scoring component to an active verification signal that guides intermediate sentence generation. Experiments on QASC, WorldTree, and WikiHop demonstrate that ITERLOGIC improves answer accuracy, highlighting the effectiveness of iterative verification for reliable multi-hop reasoning.
Anthology ID:
2026.findings-emnlp.2039
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
SIG:
SIGDAT
Publisher:
Association for Computational Linguistics
Note:
Pages:
43407–43419
Language:
URL:
https://aclanthology.org/2026.findings-emnlp.2039/
DOI:
10.18653/2026.findings-emnlp.2039
Bibkey:
Cite (ACL):
Jihao Shi, Liang Yang, and Hongfei Lin. 2026. Iterative Natural Logic Verification for Multi-hop Question Answering. In Findings of the Association for Computational Linguistics: EMNLP 2026, pages 43407–43419, Budapest, Hungary. Association for Computational Linguistics.
Cite (Informal):
Iterative Natural Logic Verification for Multi-hop Question Answering (Shi et al., Findings 2026)
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PDF:
https://aclanthology.org/2026.findings-emnlp.2039.pdf