English

Measuring Dead Directions: Decomposing and Classifying Singular Structure off Canonical Alignment

Machine Learning 2026-07-01 v1

Abstract

We give a descent-free, alignment-free measurement of singular structure on trained networks. At a single frozen checkpoint the read recovers the order kk of each dead direction from the directional-Fisher rate, the master invariant from which the per-direction learning coefficient 1/(2k)1/(2k) follows exactly, in whatever basis the optimizer left. The same read classifies each direction, separating a genuine singularity, whose order the architecture fixes, from a flat gauge symmetry; the directional-Fisher magnitude settles the cases the order cannot. A pluggable detector supplies the directions for transformer, convolutional, and normalisation layers. The read recovers the architecture-predicted order across constructed cells and trained networks, including a fine-tuned vision transformer whose dead structure is the LayerNorm-kernel gauge and a from-scratch one whose compressed MLP forms a node-death at its activation order. Where the singular structure enumerates, the per-direction orders assemble, through the typed intersection of the loci, into the global coefficient (λ,m)(\lambda, m) matching the closed form. The method removes the canonical-alignment and descent preconditions of the underlying rate result, turning order-recovery into a deterministic, architecture-general reading. We then map its reach into the Watanabe triple: the order determines the universal singular fluctuation ν(k)\nu(k), though a trained network's realized ν\nu falls below it as the live structure absorbs the dead direction's data fluctuation, and the multiplicity recovers from the dominant structure under a single-locus assumption.

Cite

@article{arxiv.2607.00603,
  title  = {Measuring Dead Directions: Decomposing and Classifying Singular Structure off Canonical Alignment},
  author = {Tejas Pradeep Shirodkar},
  journal= {arXiv preprint arXiv:2607.00603},
  year   = {2026}
}

Comments

45 pages, 14 figures, 19 tables. Methods and empirical companion to arXiv:2606.05957 (Dead Directions: Geometric Singular Learning)