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In this paper, we first introduce the concept of an adaptive MRA (AMRA) structure which is a variant of the classical MRA structure suited to the main goal of a fast flexible decomposition strategy adapted to the data at each decomposition…

Numerical Analysis · Mathematics 2009-12-24 Bin Han , Gitta Kutyniok , Zuowei Shen

The framework of document spanners abstracts the task of information extraction from text as a function that maps every document (a string) into a relation over the document's spans (intervals identified by their start and end indices). For…

Databases · Computer Science 2023-06-22 Johannes Doleschal , Benny Kimelfeld , Wim Martens , Liat Peterfreund

Many applications, especially in physics and other sciences, call for easily interpretable and robust machine learning techniques. We propose a fully gradient-based technique for training radial basis function networks with an efficient and…

Machine Learning · Computer Science 2022-09-30 Jussi Määttä , Viacheslav Bazaliy , Jyri Kimari , Flyura Djurabekova , Kai Nordlund , Teemu Roos

We propose a tree-based algorithm for classification and regression problems in the context of functional data analysis, which allows to leverage representation learning and multiple splitting rules at the node level, reducing…

Machine Learning · Statistics 2020-11-03 Edoardo Belli , Simone Vantini

Algorithms for binary classification based on adaptive tree partitioning are formulated and analyzed for both their risk performance and their friendliness to numerical implementation. The algorithms can be viewed as generating a set…

Statistics Theory · Mathematics 2014-11-05 Peter Binev , Albert Cohen , Wolfgang Dahmen , Ronald DeVore

We study integral operators on the space of square-integrable functions from a compact set, $X$, to a separable Hilbert space, $H$. The kernel of such an operator takes values in the ideal of Hilbert-Schmidt operators on $H$. We establish…

Functional Analysis · Mathematics 2024-08-12 John Zweck , Yuri Latushkin , Erika Gallo

We use a model operator approach and the spectral theorem for self-adjoint operators in a Hilbert space to derive the basic results of abstract left-definite theory in a straightforward manner. The theory is amply illustrated with a variety…

Spectral Theory · Mathematics 2024-08-06 Christoph Fischbacher , Fritz Gesztesy , Paul Hagelstein , Lance Littlejohn

Understanding whether deep neural networks are effectively optimized remains challenging, as training occurs in highly nonconvex landscapes and standard metrics provide limited visibility into layer-wise learning quality. This challenge is…

Machine Learning · Computer Science 2026-05-05 Arian Eamaz , Farhang Yeganegi , Mojtaba Soltanalian

We prove the existence of tight frames whose elements lie on an arbitrary ellipsoidal surface within a real or complex separable Hilbert space H, and we analyze the set of attainable frame bounds. In the case where H is real and has finite…

Operator Algebras · Mathematics 2007-05-23 Ken Dykema , Dan Freeman , Keri Kornelson , David Larson , Marc Ordower , Eric Weber

Given a self-adjoint operator $T$ on a separable infinite-dimensional Hilbert space we study the problem of characterizing the set $\mathcal D(T)$ of all possible diagonals of $T$. For compact operators $T$, we give a complete…

Functional Analysis · Mathematics 2023-04-10 Marcin Bownik , John Jasper

Medical image segmentation is a critical task that plays a vital role in diagnosis, treatment planning, and disease monitoring. Accurate segmentation of anatomical structures and abnormalities from medical images can aid in the early…

Computer Vision and Pattern Recognition · Computer Science 2023-09-14 Reza Azad , Amirhossein Kazerouni , Alaa Sulaiman , Afshin Bozorgpour , Ehsan Khodapanah Aghdam , Abin Jose , Dorit Merhof

We show an algorithm that, given an $n$-vertex graph $G$ and a parameter $k$, in time $2^{O(k \log k)} n^{O(1)}$ finds a tree decomposition of $G$ with the following properties: * every adhesion of the tree decomposition is of size at most…

Data Structures and Algorithms · Computer Science 2020-09-29 Marek Cygan , Paweł Komosa , Daniel Lokshtanov , Michał Pilipczuk , Marcin Pilipczuk , Saket Saurabh , Magnus Wahlström

In this chapter, we introduce the relaxed inertial proximal splitting algorithm (RIPSA) for hierarchical equilibrium problems. Using Opial-Passty's lemma, we first establish weak ergodic and weak convergence of the sequence generated by the…

Optimization and Control · Mathematics 2025-09-30 Zakaria Mazgouri , Hassan Riahi , Michel Théra

A metric tree is a tree whose edges are viewed as line segments of positive length. The Dirac operator on such tree is the operator which operates on each edge, complemented by the matching conditions at the vertices which were given by…

Mathematical Physics · Physics 2015-07-14 Xiao Liu

This study details the development and validation of a new algorithm that determines the dominant habit plane of a transformed child phase from orientation maps of a single planar cross-section. The method describes the habit plane in terms…

Materials Science · Physics 2023-03-15 Tuomo Nyyssonen , Azdiar A. Gazder , Ralf Hielscher , Frank Niessen

Barren-plateau results have established exponential gradient suppression as a widely cited obstacle to the scalability of variational quantum algorithms. When and whether these results extend to a given objective has been addressed through…

Quantum Physics · Physics 2026-04-22 Gordon Ma , Xiufan Li

The main purpose of our paper is a new approach to design of algorithms of Kaczmarz type in the framework of operators in Hilbert space. Our applications include a diverse list of optimization problems, new Karhunen-Lo\`eve transforms, and…

Functional Analysis · Mathematics 2021-04-27 Palle E. T. Jorgensen , Myung-Sin Song , James Tian

We describe an approach for estimating the statistical risk of deep networks that contain a mix of learned and known operators. Building on the maximal training error bounds previously established for known operator learning, we derive a…

Machine Learning · Computer Science 2026-05-12 Andreas Maier , Md Hasan , Paulina Conrad , Paula Andrea Perez-Toro

The theory of direct integral decompositions of both bounded and unbounded operators is further developed; in particular, results about spectral projections, functional calculus and affiliation to von Neumann algebras are proved. For…

Operator Algebras · Mathematics 2015-09-14 Ken Dykema , Joseph Noles , Fedor Sukochev , Dmitriy Zanin

Random forests construct each tree with a different, randomised representation of the feature space. Their uniform voting cannot correct errors in regions where trees with incorrect representations probabilistically outnumber correct ones,…

Machine Learning · Computer Science 2026-05-28 Youngjoon Park