An Entropic Factor Model for Robust Portfolio Replication

arXiv:2609.03552 2026 Architecture 1 ideas extracted · analyzed Sep 4, 2026

What the math gives to ML

The paper turns an underdetermined bounded linear inverse problem into a unique convex reconstruction by minimizing separable Fermi-Dirac negative entropy over a box. Its transferable asset is not portfolio-specific: the solution remains within explicit coordinate bounds, avoids extreme allocations when constraints are weak or contradictory, and can be computed through a low-dimensional dual root solve. This suggests a principled replacement for heuristic load balancing in mixture-of-experts routing, where token allocations must satisfy capacity and conservation constraints. The most direct experiment is an entropic routing projection that converts noisy router preferences into capacity-safe expert fractions.

Ideas from this paper

Unverified 2026

Fermi-Dirac Capacity Projection for MoE Routing

Replace heuristic softmax load balancing with a convex entropic projection that computes expert assignment fractions satisfying explicit linear capacity and load constraints. The projection is bounded componentwise and keeps poorly identified routing decisions away from extreme 0/1 allocations, reducing expert collapse and overload under noisy or shifted batches.

Useful6/10
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Paper: An Entropic Factor Model for Robust Portfolio Replication arXiv:2609.03552