A Busemann hybrid projection-proximal point algorithm for optimization problems on Hadamard manifolds

Fuente: arXiv
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Main Authors: Millán, R. Díaz, Ferreira, O. P., Louzeiro, M. S., Ugon, J.
Format: Preprint
Published: 2026
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author Millán, R. Díaz
Ferreira, O. P.
Louzeiro, M. S.
Ugon, J.
author_facet Millán, R. Díaz
Ferreira, O. P.
Louzeiro, M. S.
Ugon, J.
contents We study optimization problems on Hadamard manifolds, motivated by recent advances in geometric approaches to optimization on curved spaces, particularly those involving the structure of Busemann functions. We introduce a projection based variant of the proximal point algorithm, termed the \emph{Busemann hybrid projection proximal point algorithm}, which replaces Euclidean hyperplanes with horospheres defined via convex Busemann functions. The algorithm performs projections in closed form using the gradients of these functions, resulting in a geometrically intrinsic scheme that requires no tangent space linear solves. We allow for inexact subgradient evaluations and prove global convergence under controlled inexactness, with a relative error level strictly below one. We establish a Fejér type descent and sublinear complexity with a rate proportional to the inverse square root of the iteration count, and show that the exact variant coincides with the classical Riemannian proximal point algorithm. The framework clarifies the role of Busemann based subdifferentials in optimization on spaces of nonpositive curvature.
format Preprint
id arxiv_https___arxiv_org_abs_2603_00005
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle A Busemann hybrid projection-proximal point algorithm for optimization problems on Hadamard manifolds
Millán, R. Díaz
Ferreira, O. P.
Louzeiro, M. S.
Ugon, J.
Optimization and Control
90C25, 90C26, 90C30, 65K10, 58C05
We study optimization problems on Hadamard manifolds, motivated by recent advances in geometric approaches to optimization on curved spaces, particularly those involving the structure of Busemann functions. We introduce a projection based variant of the proximal point algorithm, termed the \emph{Busemann hybrid projection proximal point algorithm}, which replaces Euclidean hyperplanes with horospheres defined via convex Busemann functions. The algorithm performs projections in closed form using the gradients of these functions, resulting in a geometrically intrinsic scheme that requires no tangent space linear solves. We allow for inexact subgradient evaluations and prove global convergence under controlled inexactness, with a relative error level strictly below one. We establish a Fejér type descent and sublinear complexity with a rate proportional to the inverse square root of the iteration count, and show that the exact variant coincides with the classical Riemannian proximal point algorithm. The framework clarifies the role of Busemann based subdifferentials in optimization on spaces of nonpositive curvature.
title A Busemann hybrid projection-proximal point algorithm for optimization problems on Hadamard manifolds
topic Optimization and Control
90C25, 90C26, 90C30, 65K10, 58C05
url https://arxiv.org/abs/2603.00005