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Main Authors: Li, Huayu, He, ZhengXiao, Tian, Siyuan, Wen, Jinghao, Li, Ao
Format: Preprint
Published: 2026
Subjects:
Online Access:https://arxiv.org/abs/2601.15482
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author Li, Huayu
He, ZhengXiao
Tian, Siyuan
Wen, Jinghao
Li, Ao
author_facet Li, Huayu
He, ZhengXiao
Tian, Siyuan
Wen, Jinghao
Li, Ao
contents Standard autoregressive decoding in large language models (LLMs) is inherently short-sighted, often failing to find globally optimal reasoning paths due to its token-by-token generation process. While inference-time strategies like foresight sampling attempt to mitigate this by simulating future steps, they typically rely on ad-hoc heuristics for valuing paths and pruning the search space. This paper introduces Martingale Foresight Sampling (MFS), a principled framework that reformulates LLM decoding as a problem of identifying an optimal stochastic process. By modeling the quality of a reasoning path as a stochastic process, we leverage Martingale theory to design a theoretically-grounded algorithm. Our approach replaces heuristic mechanisms with principles from probability theory: step valuation is derived from the Doob Decomposition Theorem to measure a path's predictable advantage, path selection uses Optional Stopping Theory for principled pruning of suboptimal candidates, and an adaptive stopping rule based on the Martingale Convergence Theorem terminates exploration once a path's quality has provably converged. Experiments on six reasoning benchmarks demonstrate that MFS surpasses state-of-the-art methods in accuracy while significantly improving computational efficiency. Code will be released at https://github.com/miraclehetech/EACL2026-Martingale-Foresight-Sampling.
format Preprint
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publishDate 2026
record_format arxiv
spellingShingle Martingale Foresight Sampling: A Principled Approach to Inference-Time LLM Decoding
Li, Huayu
He, ZhengXiao
Tian, Siyuan
Wen, Jinghao
Li, Ao
Machine Learning
Artificial Intelligence
Standard autoregressive decoding in large language models (LLMs) is inherently short-sighted, often failing to find globally optimal reasoning paths due to its token-by-token generation process. While inference-time strategies like foresight sampling attempt to mitigate this by simulating future steps, they typically rely on ad-hoc heuristics for valuing paths and pruning the search space. This paper introduces Martingale Foresight Sampling (MFS), a principled framework that reformulates LLM decoding as a problem of identifying an optimal stochastic process. By modeling the quality of a reasoning path as a stochastic process, we leverage Martingale theory to design a theoretically-grounded algorithm. Our approach replaces heuristic mechanisms with principles from probability theory: step valuation is derived from the Doob Decomposition Theorem to measure a path's predictable advantage, path selection uses Optional Stopping Theory for principled pruning of suboptimal candidates, and an adaptive stopping rule based on the Martingale Convergence Theorem terminates exploration once a path's quality has provably converged. Experiments on six reasoning benchmarks demonstrate that MFS surpasses state-of-the-art methods in accuracy while significantly improving computational efficiency. Code will be released at https://github.com/miraclehetech/EACL2026-Martingale-Foresight-Sampling.
title Martingale Foresight Sampling: A Principled Approach to Inference-Time LLM Decoding
topic Machine Learning
Artificial Intelligence
url https://arxiv.org/abs/2601.15482