Dimension-Free Convergence of Discrete Diffusion Models: Adjoint Equations Induce the Right Space

Fuente: arXiv
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Autori principali: Kan, Kelvin, Li, Xingjian, Zhang, Benjamin J., Sahai, Tuhin, Osher, Stanley, Katsoulakis, Markos A.
Natura: Preprint
Pubblicazione: 2026
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author Kan, Kelvin
Li, Xingjian
Zhang, Benjamin J.
Sahai, Tuhin
Osher, Stanley
Katsoulakis, Markos A.
author_facet Kan, Kelvin
Li, Xingjian
Zhang, Benjamin J.
Sahai, Tuhin
Osher, Stanley
Katsoulakis, Markos A.
contents Discrete diffusion has become a leading framework for generative modeling in various applications including language, vision, and biology. Existing convergence theory, however, exhibits fundamental limitations. KL-based analyses diverge under singular priors such as the masked distribution, while bounds in total variation (TV) depend on the state space size $S$ and become vacuous for modern language tasks, where vocabularies contain hundreds of thousands of tokens. We develop a unified adjoint-equation-based framework that establishes dimension-free convergence guarantees in any integral probability metric (IPM). To the best of our knowledge, our bounds are the first to be entirely free of $S$ and applicable to both masked and uniform priors. Importantly, our theory relies only on a single standard rate-matrix regularity assumption and is compatible with time-inhomogeneous schedules. Four novel techniques drive our improvements: working in the space of observables via adjoint equations rather than directly with probability measures, a regularity analysis that yields bounds on any IPM, a coupling argument that removes $S$-dependence under uniform transitions, and a score-marginal cancellation technique that removes $S$-dependence under masked transitions. Our framework thus sharply departs from prior analyses and avoids the shortcomings of pathspace-KL and existing TV-based approaches. Beyond convergence bounds, our framework provides a versatile toolkit for further theoretical study of discrete diffusion models.
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id arxiv_https___arxiv_org_abs_2605_17232
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Dimension-Free Convergence of Discrete Diffusion Models: Adjoint Equations Induce the Right Space
Kan, Kelvin
Li, Xingjian
Zhang, Benjamin J.
Sahai, Tuhin
Osher, Stanley
Katsoulakis, Markos A.
Machine Learning
Statistics Theory
Discrete diffusion has become a leading framework for generative modeling in various applications including language, vision, and biology. Existing convergence theory, however, exhibits fundamental limitations. KL-based analyses diverge under singular priors such as the masked distribution, while bounds in total variation (TV) depend on the state space size $S$ and become vacuous for modern language tasks, where vocabularies contain hundreds of thousands of tokens. We develop a unified adjoint-equation-based framework that establishes dimension-free convergence guarantees in any integral probability metric (IPM). To the best of our knowledge, our bounds are the first to be entirely free of $S$ and applicable to both masked and uniform priors. Importantly, our theory relies only on a single standard rate-matrix regularity assumption and is compatible with time-inhomogeneous schedules. Four novel techniques drive our improvements: working in the space of observables via adjoint equations rather than directly with probability measures, a regularity analysis that yields bounds on any IPM, a coupling argument that removes $S$-dependence under uniform transitions, and a score-marginal cancellation technique that removes $S$-dependence under masked transitions. Our framework thus sharply departs from prior analyses and avoids the shortcomings of pathspace-KL and existing TV-based approaches. Beyond convergence bounds, our framework provides a versatile toolkit for further theoretical study of discrete diffusion models.
title Dimension-Free Convergence of Discrete Diffusion Models: Adjoint Equations Induce the Right Space
topic Machine Learning
Statistics Theory
url https://arxiv.org/abs/2605.17232