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Keep the Best Thoughts, but Not Copies of Them

A pruning rule optimizes the chance that at least one surviving reasoning path succeeds, balancing quality against redundant trajectories.

Published Updated Story ID: mp-2026-10-23-006
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Summary

A pruning rule optimizes the chance that at least one surviving reasoning path succeeds, balancing quality against redundant trajectories.

Test-time reasoning can generate many partial solutions, then spend most of its compute finishing only a few. Pure quality scoring risks keeping near-duplicates; pure diversity can preserve weak paths. The proposed selector directly optimizes pass-at-k for the surviving pool, rewarding promising prefixes while penalizing overlap in the final answers they are likely to reach. On eight open-weight reasoning models, it outperformed the quality-only and diversity-oriented pruning baselines, with the largest gains when a moderate number of continuations survived. The result concerns the tested reasoning tasks and estimators, not a universal inference policy.

Why it matters

A pruning rule optimizes the chance that at least one surviving reasoning path succeeds, balancing quality against redundant trajectories.

Limits and context

  • Test-time reasoning can generate many partial solutions, then spend most of its compute finishing only a few.
  • On eight open-weight reasoning models, it outperformed the quality-only and diversity-oriented pruning baselines, with the largest gains when a moderate number of continuations survived.
  • The result concerns the tested reasoning tasks and estimators, not a universal inference policy.

Key claims

  1. A pruning rule optimizes the chance that at least one surviving reasoning path succeeds, balancing quality against redundant trajectories.

    Qualification: Test-time reasoning can generate many partial solutions, then spend most of its compute finishing only a few.

    Evidence: source-2026-10-23-006

Sources

  1. arXiv preprint 2610.31667, original v1arXiv · primary research

Corrections

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