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Main Authors: Wang, Yadong, Chen, Haodong, Tian, Yu, Geng, Chuanxing, Liang, Dong, Chen, Xiang
Format: Preprint
Published: 2026
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Online Access:https://arxiv.org/abs/2602.01695
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author Wang, Yadong
Chen, Haodong
Tian, Yu
Geng, Chuanxing
Liang, Dong
Chen, Xiang
author_facet Wang, Yadong
Chen, Haodong
Tian, Yu
Geng, Chuanxing
Liang, Dong
Chen, Xiang
contents Latent reasoning compresses the chain-of-thought (CoT) into continuous hidden states, yet existing methods rely on dense latent transitions that remain difficult to interpret and control. Meanwhile, sparse representation models uncover human-interpretable semantic features but remain largely confined to post-hoc analysis. We reconcile this tension by proposing LSTR (Latent Sparse Transcoder Reasoning), a latent reasoning framework that elevates functional sparse transcoders into active reasoning operators to perform multi-step computation through sparse semantic transitions. At its core, LSTR employs a Latent Transition Transcoder (LTT) with a residual skip architecture that decouples linear manifold transport from sparse semantic updates, enabling controllable semantic resolution via explicit sparsity constraints. Extensive experiments show that LSTR preserves reasoning accuracy and compression efficiency while substantially improving interpretability over dense latent baselines. Causal interventions and trajectory analyses further demonstrate that these sparse features act as both interpretable and causally effective operators in the reasoning process.
format Preprint
id arxiv_https___arxiv_org_abs_2602_01695
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Beyond Dense States: Elevating Sparse Transcoders to Active Operators for Latent Reasoning
Wang, Yadong
Chen, Haodong
Tian, Yu
Geng, Chuanxing
Liang, Dong
Chen, Xiang
Artificial Intelligence
Machine Learning
Latent reasoning compresses the chain-of-thought (CoT) into continuous hidden states, yet existing methods rely on dense latent transitions that remain difficult to interpret and control. Meanwhile, sparse representation models uncover human-interpretable semantic features but remain largely confined to post-hoc analysis. We reconcile this tension by proposing LSTR (Latent Sparse Transcoder Reasoning), a latent reasoning framework that elevates functional sparse transcoders into active reasoning operators to perform multi-step computation through sparse semantic transitions. At its core, LSTR employs a Latent Transition Transcoder (LTT) with a residual skip architecture that decouples linear manifold transport from sparse semantic updates, enabling controllable semantic resolution via explicit sparsity constraints. Extensive experiments show that LSTR preserves reasoning accuracy and compression efficiency while substantially improving interpretability over dense latent baselines. Causal interventions and trajectory analyses further demonstrate that these sparse features act as both interpretable and causally effective operators in the reasoning process.
title Beyond Dense States: Elevating Sparse Transcoders to Active Operators for Latent Reasoning
topic Artificial Intelligence
Machine Learning
url https://arxiv.org/abs/2602.01695