Segmenting Human-LLM Co-authored Text via Change Point Detection

Fuente: arXiv
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Auteurs principaux: Li, Mengchu, Zhu, Jin, Li, Jinglai, Shi, Chengchun
Format: Preprint
Publié: 2026
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author Li, Mengchu
Zhu, Jin
Li, Jinglai
Shi, Chengchun
author_facet Li, Mengchu
Zhu, Jin
Li, Jinglai
Shi, Chengchun
contents The rise of large language models (LLMs) has created an urgent need to distinguish between human-written and LLM-generated text to ensure authenticity and societal trust. Existing detectors typically provide a binary classification for an entire passage; however, this is insufficient for human--LLM co-authored text, where the objective is to localize specific segments authored by humans or LLMs. To bridge this gap, we propose algorithms to segment text into human- and LLM-authored pieces. Our key observation is that such a segmentation task is conceptually similar to classical change point detection in time-series analysis. Leveraging this analogy, we adapt change point detection to LLM-generated text detection, develop a weighted algorithm and a generalized algorithm to accommodate heterogeneous detection score variability, and establish the minimax optimality of our procedure. Empirically, we demonstrate the strong performance of our approach against a wide range of existing baselines.
format Preprint
id arxiv_https___arxiv_org_abs_2605_03723
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Segmenting Human-LLM Co-authored Text via Change Point Detection
Li, Mengchu
Zhu, Jin
Li, Jinglai
Shi, Chengchun
Computation and Language
Artificial Intelligence
Methodology
The rise of large language models (LLMs) has created an urgent need to distinguish between human-written and LLM-generated text to ensure authenticity and societal trust. Existing detectors typically provide a binary classification for an entire passage; however, this is insufficient for human--LLM co-authored text, where the objective is to localize specific segments authored by humans or LLMs. To bridge this gap, we propose algorithms to segment text into human- and LLM-authored pieces. Our key observation is that such a segmentation task is conceptually similar to classical change point detection in time-series analysis. Leveraging this analogy, we adapt change point detection to LLM-generated text detection, develop a weighted algorithm and a generalized algorithm to accommodate heterogeneous detection score variability, and establish the minimax optimality of our procedure. Empirically, we demonstrate the strong performance of our approach against a wide range of existing baselines.
title Segmenting Human-LLM Co-authored Text via Change Point Detection
topic Computation and Language
Artificial Intelligence
Methodology
url https://arxiv.org/abs/2605.03723