Constructive conditional normalizing flows

Fuente: arXiv
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Main Authors: Geshkovski, Borjan, Ruiz-Balet, Domènec
Format: Preprint
Published: 2026
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author Geshkovski, Borjan
Ruiz-Balet, Domènec
author_facet Geshkovski, Borjan
Ruiz-Balet, Domènec
contents Motivated by applications in conditional sampling, given a probability measure $μ$ and a diffeomorphism $ϕ$, we consider the problem of simultaneously approximating $ϕ$ and the pushforward $ϕ_{\#}μ$ by means of the flow of a continuity equation whose velocity field is a perceptron neural network with piecewise constant weights. We provide an explicit construction based on a polar-like decomposition of the Lagrange interpolant of $ϕ$. The latter involves a compressible component, given by the gradient of a particular convex function, which can be realized exactly, and an incompressible component, which -- after approximating via permutations -- can be implemented through shear flows intrinsic to the continuity equation. For more regular maps $ϕ$ -- such as the Knöthe-Rosenblatt rearrangement -- we provide an alternative, probabilistic construction inspired by the Maurey empirical method, in which the number of discontinuities in the weights doesn't scale inversely with the ambient dimension.
format Preprint
id arxiv_https___arxiv_org_abs_2602_08606
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Constructive conditional normalizing flows
Geshkovski, Borjan
Ruiz-Balet, Domènec
Optimization and Control
Machine Learning
Analysis of PDEs
Probability
Motivated by applications in conditional sampling, given a probability measure $μ$ and a diffeomorphism $ϕ$, we consider the problem of simultaneously approximating $ϕ$ and the pushforward $ϕ_{\#}μ$ by means of the flow of a continuity equation whose velocity field is a perceptron neural network with piecewise constant weights. We provide an explicit construction based on a polar-like decomposition of the Lagrange interpolant of $ϕ$. The latter involves a compressible component, given by the gradient of a particular convex function, which can be realized exactly, and an incompressible component, which -- after approximating via permutations -- can be implemented through shear flows intrinsic to the continuity equation. For more regular maps $ϕ$ -- such as the Knöthe-Rosenblatt rearrangement -- we provide an alternative, probabilistic construction inspired by the Maurey empirical method, in which the number of discontinuities in the weights doesn't scale inversely with the ambient dimension.
title Constructive conditional normalizing flows
topic Optimization and Control
Machine Learning
Analysis of PDEs
Probability
url https://arxiv.org/abs/2602.08606