arXiv Computation and Language

Align, Unify, Suppress, Route: A Coherentist View of Transformer Computation

arXiv AI
3d ago

Effective Does Not Mean Useful: Conditional Functional Substitutability for Redundancy and Scaling in Transformers

The paper introduces Conditional Functional Substitutability (CFS) as a new way to measure redundancy in Transformers by examining when intermediate states produce similar downstream responses. CFS uncovers functional relationships and potential reductions that traditional importance- or similarity-based metrics miss, revealing systematic reorganization as models scale. Experiments across modalities and Transformer families show that performance gains do not always align with increased substitutability, and that models with more independent functional structure perform better, offering a functional explanation for diminishing returns and enabling more efficient dynamic computation.

By Jiaheng Chen, Jiaxing Li, Yucheng Xiao, Xinyong Cai, Juncheng Bu, Lan Yu, Tinghe Zhang
arXiv AI
Jun 9

How Transformers Reject Wrong Answers: Rotational Dynamics of Factual Constraint Processing

arXiv:2603. 13259v2 Announce Type: replace-cross Abstract: When a decoder-only transformer is forced to process matched correct and incorrect single-token continuations of a factual query, the two pathways through hidden-state space diverge in a specific way: displacement vectors from the query-only representation maintain approximately equal magnitude but rotate apart in direction.

By Javier Mar\'in
arXiv Computation and Language
Aug 25

The Communication Map of a Transformer

The paper introduces the Communication Map, a method that charts every potential communication channel in a transformer model using only its weights. It generalizes previous coupling metrics into a single coefficient covering all 18 connection classes, revealing that 70‑89% of head pairs are non‑randomly oriented and identifying strong or avoiding couplings. The authors demonstrate the map’s utility by recovering known induction circuits and uncovering a two‑dimensional stream subspace whose removal eliminates induction capabilities across several models.

By Richard Zhe Wang