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Under conditions that prevent tangential intersection, we prove quadratic convergence of a projection algorithm for the feasibility problem of finding a point in the intersection of a smooth curve and line in $\mathbb{R}^2$. This nonconvex…

Optimization and Control · Mathematics 2025-10-22 Jordan Collard , Scott B. Lindstrom

A module over a ring $R$ is pure projective provided it is isomorphic to a direct summand of a direct sum of finitely presented modules. We develop tools for the classification of pure projective modules over commutative noetherian rings.…

Commutative Algebra · Mathematics 2023-11-10 Dolors Herbera , Pavel Příhoda , Roger Wiegand

A novel tensor-based formula for solving the linear systems involving Kronecker sum is proposed. Such systems are directly related to the matrix and tensor forms of Sylvester equation. The new tensor-based formula demonstrates the…

General Mathematics · Mathematics 2025-04-15 Ahmad Y. Al-Dweik , Abdallah Sayyed-Ahmad

We consider moduli spaces of dynamical systems of correspondences over the projective line as a generalization of moduli spaces of dynamical systems of endomorphisms on the projective line. We obtain the rationality of the moduli spaces.…

Dynamical Systems · Mathematics 2021-09-15 Rin Gotou

In the present paper we investigate Moore-Penrose inverse and characteristic matrix of unbounded WCT operators on the Hilbert space $L^2(\mu)$. Also, we obtain some applications of the Moore-Penrose inverse of unbounded operators on the…

Functional Analysis · Mathematics 2021-12-21 Yousef Estaremi , Saeedeh Shamsi

Generalized inverses of tensors play increasingly important roles in computational mathematics and numerical analysis. It is appropriate to develop the theory of generalized inverses of tensors within the algebraic structure of a ring. In…

Rings and Algebras · Mathematics 2021-09-24 Ratikanta Behera , Jajati Keshari Sahoo , R. N. Mohapatra , M. Zuhair Nashed

In this work we collect and compare to each other many different numerical methods for regularized regression problem and for the problem of projection on a hyperplane. Such problems arise, for example, as a subproblem of demand matrix…

We give a general theory of generalised inverses and we explain the link with the theory of finitely generated projective modules. All the paper is written in constrctive mathematics in Bishop style. So all results do have a clear…

Commutative Algebra · Mathematics 2018-09-25 Gema M. Díaz--Toca , Laureano Gonzalez-Vega , Henri Lombardi , Claude Quitté

The randomized row method is a popular representative of the iterative algorithm because of its efficiency in solving the overdetermined and consistent systems of linear equations. In this paper, we present an extended randomized multiple…

Numerical Analysis · Mathematics 2024-11-06 Nian-Ci Wu , Chengzhi Liu , Yatian Wang , Qian Zuo

We study linear inverse problems under the premise that the forward operator is not at hand but given indirectly through some input-output training pairs. We demonstrate that regularization by projection and variational regularization can…

Numerical Analysis · Mathematics 2020-12-30 Andrea Aspri , Yury Korolev , Otmar Scherzer

We introduce meta-factorization, a theory that describes matrix decompositions as solutions of linear matrix equations: the projector and the reconstruction equation. Meta-factorization reconstructs known factorizations, reveals their…

Numerical Analysis · Mathematics 2022-07-15 Michał P. Karpowicz

We consider the singular value statistics of products of independent random matrices. In particular we compute the corresponding averages of products of characteristic polynomials. To this aim we apply the projection formula recently…

Mathematical Physics · Physics 2017-01-31 Mario Kieburg

This paper develops an efficient algorithm for computing the Euclidean projection onto the top-k-sum constraint, a key operation in financial risk management and matrix optimization problems. Existing projection methods rely on sorting and…

Optimization and Control · Mathematics 2025-12-12 Jianting Pan , Ming Yan

A new algorithm for deciding the satisfiability of polynomial formulas over the reals is proposed. The key point of the algorithm is a new projection operator, called sample-cell projection operator, custom-made for Conflict-Driven Clause…

Logic in Computer Science · Computer Science 2020-03-05 Haokun Li , Bican Xia

We present explicit formulas for Moore-Penrose inverses of some families of set inclusion matrices arising from sets, vector spaces, and designs.

Combinatorics · Mathematics 2023-05-23 Ali Azimi , R. B. Bapat , Mohammad Farrokhi Derakhshandeh Ghouchan

This paper introduces a new Monte Carlo algorithm to invert large matrices. It is based on simultaneous coupled draws from two random vectors whose covariance is the required inverse. It can be considered a generalization of a previously…

Data Structures and Algorithms · Computer Science 2025-10-20 L. A. Garcia-Cortes , C. Cabrillo

Let S and T be vectors of positive integers with the same sum. We study the uniform distribution on the space of simple bipartite graphs with degree sequence S in one part and T in the other; equivalently, binary matrices with row sums S…

Combinatorics · Mathematics 2009-05-01 Catherine Greenhill , Brendan D. McKay

Because of the advance in technologies, modern statistical studies often encounter linear models with the number of explanatory variables much larger than the sample size. Estimation and variable selection in these high-dimensional problems…

Statistics Theory · Mathematics 2012-06-06 Jun Shao , Xinwei Deng

In this paper we show how to construct diagonal scalings for arbitrary matrix pencils $\lambda B-A$, in which both $A$ and $B$ are complex matrices (square or nonsquare). The goal of such diagonal scalings is to "balance" in some sense the…

Numerical Analysis · Mathematics 2021-08-02 Froilán M. Dopico , María C. Quintana , Paul Van Dooren

We study the alternating algorithm for the computation of the metric projection onto the closed sum of two closed subspaces in uniformly convex and uniformly smooth Banach spaces. For Banach spaces which are convex and smooth of power type,…

Functional Analysis · Mathematics 2020-10-09 Christian Bargetz , Emir Medjic