@inproceedings{lyu-etal-2026-structural,
title = "Structural Fabric of Data Shapes the Geometry of {LLM} Training",
author = "Lyu, Xinyu and
Li, Hanqi and
Zuo, Shenghan and
Yu, Kai and
Chen, Lu",
editor = "Lee, Hung-Yi and
Dev, Sunipa and
Li, Jessy and
Elliott, Desmond",
booktitle = "Findings of the {A}ssociation for {C}omputational {L}inguistics: {EMNLP} 2026",
month = oct,
year = "2026",
address = "Budapest, Hungary",
publisher = "Association for Computational Linguistics",
url = "https://aclanthology.org/2026.findings-emnlp.298/",
pages = "6312--6324",
ISBN = "979-8-89176-462-0",
abstract = "The performance of large language models is tied to the quality and organization of their training data. However, existing data metrics emphasize surface-level properties, such as sequence length or model-based quality scores, and provide limited insight into how the internal organization of data relates to optimization. We study the structural fabric of training data, defined as the pattern of semantic dependencies within a sequence. We quantify this property using dependency density, a normalized measure of effective segment-level dependencies. Across data length, domain, and format, we find that dependency density varies with data configuration: code shows higher dependency density than natural language within long-context data, and instruction-tuning mappings show higher dependency density than raw intra-input modeling. We show that coherent structural fabric is associated with a lower gradient effective rank, indicating a more concentrated optimization geometry with reduced gradient interference. We observe that this low-rank optimization regime is associated with a more stable intrinsic dimension, preserving a compact representation manifold that may mitigate representation noise and support downstream performance. These results provide a geometric perspective on how data structure relates to LLM training, linking data configuration, optimization dynamics, and model behavior through the lens of structural fabric."
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<abstract>The performance of large language models is tied to the quality and organization of their training data. However, existing data metrics emphasize surface-level properties, such as sequence length or model-based quality scores, and provide limited insight into how the internal organization of data relates to optimization. We study the structural fabric of training data, defined as the pattern of semantic dependencies within a sequence. We quantify this property using dependency density, a normalized measure of effective segment-level dependencies. Across data length, domain, and format, we find that dependency density varies with data configuration: code shows higher dependency density than natural language within long-context data, and instruction-tuning mappings show higher dependency density than raw intra-input modeling. We show that coherent structural fabric is associated with a lower gradient effective rank, indicating a more concentrated optimization geometry with reduced gradient interference. We observe that this low-rank optimization regime is associated with a more stable intrinsic dimension, preserving a compact representation manifold that may mitigate representation noise and support downstream performance. These results provide a geometric perspective on how data structure relates to LLM training, linking data configuration, optimization dynamics, and model behavior through the lens of structural fabric.</abstract>
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%0 Conference Proceedings
%T Structural Fabric of Data Shapes the Geometry of LLM Training
%A Lyu, Xinyu
%A Li, Hanqi
%A Zuo, Shenghan
%A Yu, Kai
%A Chen, Lu
%Y Lee, Hung-Yi
%Y Dev, Sunipa
%Y Li, Jessy
%Y Elliott, Desmond
%S Findings of the Association for Computational Linguistics: EMNLP 2026
%D 2026
%8 October
%I Association for Computational Linguistics
%C Budapest, Hungary
%@ 979-8-89176-462-0
%F lyu-etal-2026-structural
%X The performance of large language models is tied to the quality and organization of their training data. However, existing data metrics emphasize surface-level properties, such as sequence length or model-based quality scores, and provide limited insight into how the internal organization of data relates to optimization. We study the structural fabric of training data, defined as the pattern of semantic dependencies within a sequence. We quantify this property using dependency density, a normalized measure of effective segment-level dependencies. Across data length, domain, and format, we find that dependency density varies with data configuration: code shows higher dependency density than natural language within long-context data, and instruction-tuning mappings show higher dependency density than raw intra-input modeling. We show that coherent structural fabric is associated with a lower gradient effective rank, indicating a more concentrated optimization geometry with reduced gradient interference. We observe that this low-rank optimization regime is associated with a more stable intrinsic dimension, preserving a compact representation manifold that may mitigate representation noise and support downstream performance. These results provide a geometric perspective on how data structure relates to LLM training, linking data configuration, optimization dynamics, and model behavior through the lens of structural fabric.
%U https://aclanthology.org/2026.findings-emnlp.298/
%P 6312-6324
Markdown (Informal)
[Structural Fabric of Data Shapes the Geometry of LLM Training](https://aclanthology.org/2026.findings-emnlp.298/) (Lyu et al., Findings 2026)
ACL