MATH · IN · MODELS

Hierarchical Reasoning Model (HRM)

Sapient Intelligence / academic (Wang et al. 2025)

Structures found in this family (1)

Fixed-point graph topology (population-level universality of RNN dynamical structure)

By model (1)

Hierarchical Reasoning Model (~27M, trained from scratch per task, e.g. Sudoku-Extreme) · 27M
Fixed-point graph topology (population-level universality of RNN dynamical structure)

Observations (1)

A real trained Hierarchical Reasoning Model's recurrent dynamics develop multiple fixed points rather than a single one, and the model 'guesses' by converging to whichever fixed point it reaches first -- which can be wrong even on trivially simple puzzles

Papers

Are Your Reasoning Models Reasoning or Guessing? A Mechanistic Analysis of Hierarchical Reasoning Models (2026)