Training Large Language Models To Reason In Parallel With Global Forking Tokens

ICLR 2026 Conference SubmissionAnonymous Authors
large language modelreasoningchain of thoughts
Abstract:

Although LLMs have demonstrated improved performance by scaling parallel test-time compute, doing so relies on generating reasoning paths that are both diverse and accurate. For challenging problems, the forking tokens that trigger diverse yet correct reasoning modes are typically deep in the sampling tree. Consequently, common strategies to encourage diversity, such as temperature scaling, encounter a worsened trade-off between diversity and accuracy. Motivated by this challenge, we treat parallel reasoning as a set-of-next-token-prediction problem and incorporate a set-based global loss into Supervised Fine-Tuning (SFT) using bipartite matching between global forking tokens and unique reasoning traces. We observe that, whereas naive fine-tuning with multiple reasoning traces collapses these unique reasoning modes, our proposed method, Set Supervised Fine-Tuning (SSFT), preserves these modes and produces emergent global forking tokens. Experiments on multiple reasoning benchmarks show our SSFT method consistently outperforms SFT under both pass@1 and cons@k metrics.

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This report is AI-GENERATED using Large Language Models and WisPaper (A scholar search engine). It analyzes academic papers' tasks and contributions against retrieved prior work. While this system identifies POTENTIAL overlaps and novel directions, ITS COVERAGE IS NOT EXHAUSTIVE AND JUDGMENTS ARE APPROXIMATE. These results are intended to assist human reviewers and SHOULD NOT be relied upon as a definitive verdict on novelty.
NOTE that some papers exist in multiple, slightly different versions (e.g., with different titles or URLs). The system may retrieve several versions of the same underlying work. The current automated pipeline does not reliably align or distinguish these cases, so human reviewers will need to disambiguate them manually.
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Overview

Overall Novelty Assessment

The paper introduces Set Supervised Fine-Tuning (SSFT), which treats parallel reasoning as a set-of-next-token-prediction problem and uses bipartite matching to align global forking tokens with diverse reasoning traces. This work resides in the 'Supervised Fine-Tuning with Diverse Reasoning Traces' leaf, which contains only three papers total. This is a relatively sparse research direction within the broader taxonomy of fifty papers, suggesting the specific approach of preserving reasoning mode diversity through set-based losses during supervised fine-tuning remains underexplored compared to other parallel reasoning strategies.

The taxonomy reveals that this leaf sits within 'Training and Optimization Methods for Parallel Reasoning', adjacent to reinforcement learning approaches and distinct from inference-time frameworks. Neighboring branches include tree-based exploration structures, multi-agent collaboration, and adaptive path selection methods. The scope note explicitly excludes inference-time frameworks and internal mechanistic analyses, positioning this work as fundamentally about training methodology rather than architectural design or runtime optimization. The sibling papers in this leaf similarly focus on supervised learning from diverse traces, but the taxonomy structure shows this training-centric approach represents only one of several major paradigms for achieving parallel reasoning.

Across three identified contributions, the analysis examined twenty-six candidate papers total, with ten candidates reviewed for the core SSFT method and the set-prediction formulation, and six for the scalable training implementation. Critically, zero refutable candidates were found for any contribution among this limited search scope. The statistics indicate that within the top-K semantic matches and citation expansion examined, no prior work appears to directly overlap with the set-based global loss formulation or the emergent global forking token mechanism. However, this reflects the bounded search strategy rather than an exhaustive literature review, and the sparse population of the taxonomy leaf suggests limited prior exploration of this specific training paradigm.

Given the limited search scope of twenty-six candidates and the sparse three-paper leaf, the work appears to occupy a relatively novel position within supervised fine-tuning approaches for parallel reasoning. The absence of refutable candidates across all contributions suggests distinctiveness in the set-prediction formulation and bipartite matching mechanism, though this assessment is constrained by the top-K semantic search methodology and does not capture potential related work outside the examined candidate set or in adjacent machine learning subfields beyond parallel reasoning.

Taxonomy

Core-task Taxonomy Papers
50
3
Claimed Contributions
26
Contribution Candidate Papers Compared
0
Refutable Paper

Research Landscape Overview

Core task: parallel reasoning with diverse reasoning paths. The field has evolved around the idea of generating and leveraging multiple reasoning trajectories simultaneously, rather than relying on a single chain of thought. The taxonomy reveals several major branches: Multi-Path Reasoning Frameworks and Architectures establish foundational structures such as tree-based and graph-based exploration methods (e.g., Tree of Thoughts[8]), while Training and Optimization Methods focus on how to effectively learn from diverse reasoning traces through supervised fine-tuning, reinforcement learning, and other optimization strategies. Inference-Time Scaling and Optimization addresses computational efficiency when deploying parallel reasoning at scale, and Domain-Specific Applications demonstrate how these techniques adapt to tasks ranging from code synthesis to visual reasoning. Additional branches cover internal mechanisms, theoretical foundations, and alternative paradigms that challenge the need for explicit multi-step reasoning. Within the training and optimization landscape, a particularly active line of work explores how to fine-tune models using collections of diverse reasoning paths. Global Forking Tokens[0] sits squarely in this area, proposing a mechanism to encourage branching during supervised learning. Nearby efforts such as Diverse Reasoning Chains[11] and Reasoning Path Divergence[48] similarly emphasize the value of training on varied solution strategies, though they differ in how divergence is measured or enforced. These approaches contrast with methods that rely primarily on reinforcement learning or search-time aggregation, highlighting an ongoing question: should diversity be baked into the training data and model architecture, or emerge dynamically during inference? By focusing on supervised fine-tuning with explicit forking tokens, Global Forking Tokens[0] aligns closely with works that treat path diversity as a first-class training objective, offering a structured way to instill parallel reasoning capabilities directly into the model's learned representations.

Claimed Contributions

Set Supervised Fine-Tuning (SSFT) with global forking tokens

The authors propose SSFT, a training method that uses bipartite matching to align reserved special tokens (global forking tokens) with diverse reasoning traces. This set-based loss enables the model to learn tokens that trigger distinct reasoning modes without collapsing them, improving both diversity and accuracy in parallel reasoning.

10 retrieved papers
Formulation of parallel reasoning as set-of-next-token-prediction

The authors frame parallel reasoning as predicting a set of reasoning sequences rather than individual sequences. This formulation incorporates permutation-invariance and uses minimum-cost bipartite matching to assign global forking tokens to reasoning traces, naturally embedding coverage into the training objective.

10 retrieved papers
Scalable training implementation for variable-size parallel generation

The authors develop a training algorithm that expands variable-sized parallel generations along the batch dimension under distributed training instead of concatenating diverse reasoning traces. This approach avoids additional VRAM overhead while supporting flexible numbers of reasoning targets per question.

6 retrieved papers

Core Task Comparisons

Comparisons with papers in the same taxonomy category

Contribution Analysis

Detailed comparisons for each claimed contribution

Contribution

Set Supervised Fine-Tuning (SSFT) with global forking tokens

The authors propose SSFT, a training method that uses bipartite matching to align reserved special tokens (global forking tokens) with diverse reasoning traces. This set-based loss enables the model to learn tokens that trigger distinct reasoning modes without collapsing them, improving both diversity and accuracy in parallel reasoning.

Contribution

Formulation of parallel reasoning as set-of-next-token-prediction

The authors frame parallel reasoning as predicting a set of reasoning sequences rather than individual sequences. This formulation incorporates permutation-invariance and uses minimum-cost bipartite matching to assign global forking tokens to reasoning traces, naturally embedding coverage into the training objective.

Contribution

Scalable training implementation for variable-size parallel generation

The authors develop a training algorithm that expands variable-sized parallel generations along the batch dimension under distributed training instead of concatenating diverse reasoning traces. This approach avoids additional VRAM overhead while supporting flexible numbers of reasoning targets per question.