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It is a fundamental result in commutative algebra and invariant theory that a finitely generated graded module over a commutative finitely generated graded algebra has rational Hilbert series, and consequently the Hilbert series of the…

Rings and Algebras · Mathematics 2017-08-22 M. Domokos , V. Drensky

We present results and examples which show that the consideration of a certain tubular mutation is advantageous in the study of noncommutative curves which parametrize the simple regular representations of a tame bimodule. We classify all…

Representation Theory · Mathematics 2008-06-16 Dirk Kussin

Compared to the entrywise transforms which preserve positive semidefiniteness, those leaving invariant the inertia of symmetric matrices reveal a surprising rigidity. We first obtain the classification of negativity preservers by combining…

Classical Analysis and ODEs · Mathematics 2026-04-14 Alexander Belton , Dominique Guillot , Apoorva Khare , Mihai Putinar

Kernel methods are powerful tools in machine learning. Classical kernel methods are based on positive-definite kernels, which map data spaces into reproducing kernel Hilbert spaces (RKHS). For non-Euclidean data spaces, positive-definite…

Machine Learning · Computer Science 2024-07-31 Nathael Da Costa , Cyrus Mostajeran , Juan-Pablo Ortega , Salem Said

We say that a symmetric noncommutative polynomial in the noncommutative free variables (x_1, x_2, ..., x_g) is noncommutative plurisubharmonic on a noncommutative open set if it has a noncommutative complex hessian that is positive…

Operator Algebras · Mathematics 2011-01-17 Jeremy M. Greene

From \cite{re} From \cite{re} it is known that ``translation-invariant Gibbs measures" of the model with an uncountable set of spin values can be described by positive fixed points of a nonlinear integral operator of Hammerstein type. In…

Functional Analysis · Mathematics 2023-06-16 I. M. Mavlonov , Kh. N. Khushvaktov , G. P. Arzikulov , F. H. Haydarov

The positive definiteness of real quadratic forms with convolution structures plays an important role in stability analysis for time-stepping schemes for nonlocal operators.In this work, we present a novel analysis tool to handle discrete…

Numerical Analysis · Mathematics 2023-11-23 Hong-lin Liao , Tao Tang , Tao Zhou

We prove a version of the classical 'generic smoothness' theorem with smooth varieties replaced by non-commutative resolutions of singular varieties. This in particular implies a non-commutative version of the Bertini theorem.

Algebraic Geometry · Mathematics 2020-06-23 Jørgen Vold Rennemo , Ed Segal , Michel Van den Bergh

Positive semidefinite Hermitian matrices that are not fully specified can be completed provided their underlying graph is chordal. If the matrix is positive definite the completion can be uniquely characterized as the matrix that maximizes…

Rings and Algebras · Mathematics 2021-12-08 Olaf Dreyer

We consider nonnegative r-potent matrices with finite dimensions and study their decomposability. We derive the precise conditions under which an r-potent matrix is decomposable. We further determine a general structure for the r-potent…

Functional Analysis · Mathematics 2015-04-20 Rashmi Sehgal Thukral , Alka Marwaha

We show in this article that if a holomorphic vector bundle has a nonnegative Hermitian metric in the sense of Bott and Chern, which always exists on globally generated holomorphic vector bundles, then some special linear combinations of…

Differential Geometry · Mathematics 2020-03-05 Ping Li

We prove that the algebraic set of pairs of matrices with a diagonal commutator over a field of positive prime characteristic, its irreducible components, and their intersection are $F$-pure when the size of matrices is equal to 3.…

Commutative Algebra · Mathematics 2017-12-15 Zhibek Kadyrsizova

Let Y be the variety of (skew) symmetric nxn-matrices of rank less than or equal to r. In paper we construct a full faithful embedding between the derived category of a non-commutative resolution of Y, constructed earlier by the authors,…

Algebraic Geometry · Mathematics 2016-05-17 Špela Špenko , Michel Van den Bergh

The concept of a fully interlacing matrix of formal power series with real coefficients is introduced. This concept extends and strengthens that of an interlacing sequence of real-rooted polynomials with nonnegative coefficients, in the…

Combinatorics · Mathematics 2024-04-22 Christos A. Athanasiadis , David G. Wagner

An $n\times n$ symmetric matrix $A$ is copositive if the quadratic form $x^TAx$ is nonnegative on the nonnegative orthant $\mathbb{R}^{n}_{\geq 0}$. The cone of copositive matrices contains the cone of matrices which are the sum of a…

Functional Analysis · Mathematics 2025-02-28 Tea Štrekelj , Aljaž Zalar

In this paper we show how specific families of positive definite kernels serve as powerful tools in analyses of iteration algorithms for multiple layer feedforward Neural Network models. Our focus is on particular kernels that adapt well to…

Machine Learning · Computer Science 2023-01-09 Palle E. T. Jorgensen , Myung-Sin Song , James Tian

We show that a matrix is a Hermitian positive semidefinite matrix whose nonzero entries have modulus 1 if and only if it similar to a direct sum of all $1's$ matrices and a 0 matrix via a unitary monomial similarity. In particular, the only…

Rings and Algebras · Mathematics 2007-05-23 Daniel Hershkowitz , Michael Neumann , Hans Schneider

A $n$-by-$n$ matrix is called totally positive ($TP$) if all its minors are positive and $TP_k$ if all of its $k$-by-$k$ submatrices are $TP$. For an arbitrary totally positive matrix or $TP_k$ matrix, we investigate if the $r$th compound…

Combinatorics · Mathematics 2024-05-13 Shaun Fallat , Himanshu Gupta , Charles R. Johnson

Nonparametric two sample testing deals with the question of consistently deciding if two distributions are different, given samples from both, without making any parametric assumptions about the form of the distributions. The current…

Statistics Theory · Mathematics 2014-11-25 Aaditya Ramdas , Sashank J. Reddi , Barnabas Poczos , Aarti Singh , Larry Wasserman

Given a linear recurrence sequence (LRS) over the integers, the Positivity Problem} asks whether all terms of the sequence are positive. We show that, for simple LRS (those whose characteristic polynomial has no repeated roots) of order 9…

Discrete Mathematics · Computer Science 2014-04-29 Joel Ouaknine , James Worrell