Entropy-Smooth Convex Optimization Cannot Be Accelerated

arXiv:2607.27476 2026 Optimization 1 ideas extracted · analyzed Aug 31, 2026

What the math gives to ML

The paper proves that convex objectives relatively smooth with respect to negative Shannon entropy cannot generally obtain an accelerated O(1/T^2) rate: when the simplex dimension satisfies d=Omega(T^2), every first-order method has error at least Omega(L/T). The transferable asset is a principled warning against blindly adding Euclidean or Nesterov momentum to high-dimensional probability-valued neural variables. A practical experiment is to use entropy mirror descent for MoE router probabilities, attention distributions, or mixture weights and compare it with accelerated updates under matched gradient evaluations.

Ideas from this paper

Unverified 2026

Entropy-Geometry Anti-Acceleration Optimizer

Replace Euclidean momentum updates on simplex-valued neural variables with entropy mirror descent when the variable dimension is large and the loss is naturally smooth relative to negative entropy. The lower bound predicts that Nesterov-style acceleration cannot guarantee an asymptotic improvement in this geometry, while the geometry-matched update preserves positivity and can reduce boundary instability.

Useful6/10
Difficulty4/10
Novelty4/10
Paper: Entropy-Smooth Convex Optimization Cannot Be Accelerated arXiv:2607.27476