Multi-Step Knowledge Interaction Analysis via Rank-2 Subspace Disentanglement

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Hauptverfasser: Islam, Sekh Mainul, Atanasova, Pepa, Augenstein, Isabelle
Format: Preprint
Veröffentlicht: 2025
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author Islam, Sekh Mainul
Atanasova, Pepa
Augenstein, Isabelle
author_facet Islam, Sekh Mainul
Atanasova, Pepa
Augenstein, Isabelle
contents Natural Language Explanations (NLEs) describe how Large Language Models (LLMs) make decisions by drawing on external Context Knowledge (CK) and Parametric Knowledge (PK). Understanding the interaction between these sources is key to assessing NLE grounding, yet these dynamics remain underexplored. Prior work has largely focused on (1) single-step generation and (2) modelled PK-CK interaction as a binary choice within a rank-1 subspace. This approach overlooks richer interactions and how they unfold over longer generations, such as complementary or supportive knowledge. We propose a novel rank-2 projection subspace that disentangles PK and CK contributions more accurately and use it for the first multi-step analysis of knowledge interactions across longer NLE sequences. Experiments across four QA datasets and three open-weight LLMs demonstrate that while rank-1 subspaces struggle to represent diverse interactions, our rank-2 formulation captures them effectively, highlighting PK alignment for supportive interactions and CK alignment for conflicting ones. Our multi-step analysis reveals, among others, that hallucinated generations exhibit strong alignment with the PK direction, whereas context-faithful generations maintain a more balanced alignment between PK and CK.
format Preprint
id arxiv_https___arxiv_org_abs_2511_01706
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Multi-Step Knowledge Interaction Analysis via Rank-2 Subspace Disentanglement
Islam, Sekh Mainul
Atanasova, Pepa
Augenstein, Isabelle
Computation and Language
Artificial Intelligence
Machine Learning
Natural Language Explanations (NLEs) describe how Large Language Models (LLMs) make decisions by drawing on external Context Knowledge (CK) and Parametric Knowledge (PK). Understanding the interaction between these sources is key to assessing NLE grounding, yet these dynamics remain underexplored. Prior work has largely focused on (1) single-step generation and (2) modelled PK-CK interaction as a binary choice within a rank-1 subspace. This approach overlooks richer interactions and how they unfold over longer generations, such as complementary or supportive knowledge. We propose a novel rank-2 projection subspace that disentangles PK and CK contributions more accurately and use it for the first multi-step analysis of knowledge interactions across longer NLE sequences. Experiments across four QA datasets and three open-weight LLMs demonstrate that while rank-1 subspaces struggle to represent diverse interactions, our rank-2 formulation captures them effectively, highlighting PK alignment for supportive interactions and CK alignment for conflicting ones. Our multi-step analysis reveals, among others, that hallucinated generations exhibit strong alignment with the PK direction, whereas context-faithful generations maintain a more balanced alignment between PK and CK.
title Multi-Step Knowledge Interaction Analysis via Rank-2 Subspace Disentanglement
topic Computation and Language
Artificial Intelligence
Machine Learning
url https://arxiv.org/abs/2511.01706