pith:DMMM25JR
A Fourier perspective on the learning dynamics of neural networks: from sample complexities to mechanistic insights
Online SGD cannot learn phase-only classification on isotropic high-dimensional inputs before order N cubed steps, but power-law spectra accelerate it substantially.
arxiv:2605.16913 v1 · 2026-05-16 · stat.ML · cond-mat.dis-nn · cond-mat.stat-mech · cs.LG · math.PR
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Claims
For isotropic and high-dimensional inputs, classification based on phase information alone is a genuinely hard task: online SGD cannot distinguish the structured inputs from noise within n ≪ N³ steps, but needs at least n ≫ N³ log²N steps.
The introduced synthetic data model for translation-invariant inputs faithfully captures the interaction between amplitudes, phases, and learning dynamics without introducing artifacts that invalidate the hardness result or the power-law acceleration claim.
Neural networks prioritize amplitude over phase in Fourier space during training on translation-invariant data; power-law spectra accelerate phase learning despite not aiding classification.
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| First computed | 2026-05-20T00:03:29.862957Z |
|---|---|
| Builder | pith-number-builder-2026-05-17-v1 |
| Signature | Pith Ed25519
(pith-v1-2026-05) · public key |
| Schema | pith-number/v1.0 |
Canonical hash
1b18cd7531b1c3d097c72e442379fb3facb2fa2df17c24134cd20b8db0c6f24c
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curl -sH 'Accept: application/ld+json' https://pith.science/pith/DMMM25JRWHB5BF6HFZCCG6P3H6 \
| jq -c '.canonical_record' \
| python3 -c "import sys,json,hashlib; b=json.dumps(json.loads(sys.stdin.read()), sort_keys=True, separators=(',',':'), ensure_ascii=False).encode(); print(hashlib.sha256(b).hexdigest())"
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Canonical record JSON
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