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Image Analysis & Stereology

Publisher:
—
ISSN:
1580-3139
Category:
MATHEMATICS, APPLIED
Impact factor:
0.8

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2 parsed articles

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Latest articles

Monotone Vector Fields and Proximal Algorithms in G-Metric Spaces: A Comprehensive Framework With Applications to Modern Optimization Challenges

2026-03-26

G Sudhaamsh Mohan Reddy, Haitham Qawaqneh

Advances in optimization theory have been made systematically by the desire to solve more and more complicated geometric structures that are realised in contemporary applications. This is a rigorous investigation of monotone vector fields and proximal algorithms in the deep geometrical setting of generalized metric spaces (G-metric spaces). Our study fills a general deficiency in the literature by generalizing classical monotonicity principles and proximal point algorithms to support the complex three-point distance structure of G-metric spaces. In this way, by conducting a strict theoretical study, we prove the existence and uniqueness of solutions in the concept of monotone inclusion, are able to develop effective proximal algorithms with guaranteed convergence rates, and illustrate their successful application in different areas of practice. Theoretical contributions that we have made include: (1) the extension of monotonicity theory in all its forms to G-metric spaces with complete characterizations, (2) the construction of strongly convergent proximal point algorithms that are explicit in rate of convergence, and (3) its application to variational inequalities and multi-objective optimization problems in non-standard geometries, where the old metric structures are no longer applicable. Our findings create new opportunities to deal with optimization problems in complex networks, social systems, and the present-day machine learning paradigms.

Exactness and Ordering in Discrete Cavalieri Sampling

2026-03-07

Francisco Javier Soto Sánchez

We study the discrete Cavalieri estimator under systematic sampling from a finite population, which models an object represented by a finite sequence of blocks along a sampling axis. For a fixed population size and a sample size that divides it, we characterize when the estimator has zero variance, namely exactness, through an explicit balance condition that characterizes the zero-variance populations; this turns out to be a simple linear family. We then ask when exactness continues to hold if the sample size is allowed to vary within the even divisors of an even population size. In that case, we prove that exactness across all such even sample sizes necessarily implies the matched-pairs condition that is known to be sufficient at a fixed even sample size. We also derive a variance formula showing that it depends only on how much the sums over certain groups differ from their average. This leads to a concrete partitioning objective for choosing an ordering and helps explain why exact optimization quickly becomes impractical. Guided by this objective and by smooth fractionator practice, we discuss simple heuristics and show that a pairing-based ordering is exact under a simple affine model and remains stable under bounded perturbations.