LogicDiff: Logic-Guided Denoising Improves Zero-Shot Reasoning in Masked Diffusion Language Models
On the map: LLM reasoning → Diffusion reasoning and test-time scaling
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Abstract (arXiv)
Masked diffusion language models (MDLMs) generate text by iteratively unmasking tokens from a fully masked sequence. Their standard confidence-based unmasking strategy systematically defers high-entropy logical connective tokens, degrading reasoning performance. We introduce LogicDiff, an inference-time method that replaces confidence-based unmasking with logic-role-guided unmasking. A lightweight classification head (4.2M parameters, 0.05% of the base model) predicts the logical role of each masked position (premise, connective, derived step, conclusion, or filler) from the base model's hidden states with 98.4% accuracy, and a dependency-ordered scheduler unmasks tokens in logical order. In zero-shot settings, LogicDiff improves LLaDA-8B-Instruct accuracy from 22.0% to 60.7% on GSM8K (+38.7 percentage points) and from 23.6% to 29.2% on MATH-500 (+5.6 pp), with less than 6% speed overhead. However, with 8-shot chain-of-thought prompting, the baseline reaches approximately 70% and LogicDiff provides no additional improvement. Analysis reveals that few-shot prompting implicitly resolves the same ordering problem that LogicDiff explicitly addresses, and that fixed role-based ordering can cause premature commitment to numerical values before sufficient context is available. Our results characterize the Flexibility Trap as primarily a zero-shot phenomenon and identify context-adaptive ordering as a key direction for future work.
Key facts. Cited by 1 paper in the map (data through 7 Oct 2026). Placed in Diffusion reasoning and test-time scaling, one of 17 directions in LLM reasoning. Builds on 9 of its 17 references that are in the map. First posted on arXiv 24 Mar 2026.
Builds on
9 of 17 references.
Closest ancestors · 5
Same direction, newest first
- 2026Test-Time Scaling with Diffusion Language Models via Reward-Guided Stitching26 Feb
- 2026The Flexibility Trap: Rethinking the Value of Arbitrary Order in Diffusion Language Models21 Jan
- 2025Reasoning in Diffusion Large Language Models is Concentrated in Dynamic Confusion Zones19 Nov
- 2025Advancing Reasoning in Diffusion Language Models with Denoising Process Rewards2 Oct
- 2025d1: Scaling Reasoning in Diffusion Large Language Models via Reinforcement Learning16 Apr
Other references · 4
- 2021Training Verifiers to Solve Math Word Problemscited by 9,743
- 2025Large Language Diffusion Modelscited by 872
- 2026Autoregressive Models Rival Diffusion Models at ANY-ORDER Generationcited by 3
- 2026DOS: Dependency-Oriented Sampler for Masked Diffusion Language Modelscited by 2
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Citing papers per year: 2026: 1.
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Close in wording, no citation either way
- 2025Plan for Speed: Dilated Scheduling for Masked Diffusion Language Models
- 2026Where-to-Unmask: Ground-Truth-Guided Unmasking Order Learning for Masked Diffusion Language Models
- 2026Pivot-SD: Efficient Self-Distillation for Masked Diffusion Language Models
- 2025Lookahead Unmasking Elicits Accurate Decoding in Diffusion Language Models
- 2026Remask, Don't Replace: Token-to-Mask Refinement in Diffusion Language Models
- 2026CAI-DLLM: Convergence Aware Inference for Diffusion Language Models
- 2025Improving Discrete Diffusion Unmasking Policies Beyond Explicit Reference Policies
- 2026NAVIRA: Decoupled Stochastic Remasking for Masked Diffusion Language Models