TopK Sparse Autoencoders Across Three Model Architectures: Dictionary Collapse, Dense-Feature Degeneracy, and the Limits of Activation-Pattern Feature Matching
TopK SAEs trained at matched sparsity and dictionary size on Llama-3.2-3B, Mistral-7B-v0.3 and Qwen2.5-3B. Reports abrupt dictionary collapse with partial recovery, dense-feature degeneracy invalidating frequency-based feature selection, and a null cross-architecture matching result whose detection floor is measured by planted-signal power analysis (MDES 0.95-1.00).
Authors
- J. Melton
Institutions
- American Standard (United States) (US)
Publication Details
- Journal
- Zenodo (CERN European Organization for Nuclear Research)
- Published
- 2026-08-14
- DOI
- https://doi.org/10.5281/zenodo.21906712
- Primary Topic
- Domain Adaptation and Few-Shot Learning
- Type
- preprint