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In this paper, we take an axiomatic approach to defining a population hierarchical clustering for piecewise constant densities, and in a similar manner to Lebesgue integration, extend this definition to more general densities. When the…

Machine Learning · Statistics 2024-07-08 Ery Arias-Castro , Elizabeth Coda

One of the main obstacle to study compactness in topological spaces via ideals was the definition of ideal convergence of subsequences as in the existing literature according to which subsequence of an ideal convergent sequence may fail to…

General Topology · Mathematics 2021-07-02 Manoranjan Singha , Sima Roy

Several methods have been proposed to estimate the number of clusters in a dataset; the basic ideal behind all of them has been to study an index that measures inter-cluster separation and intra-cluster cohesion over a range of cluster…

Computer Vision and Pattern Recognition · Computer Science 2016-01-12 Bhaskar Mukhoty , Ruchir Gupta , Y. N. Singh

Given an ideal $\mathcal{I}$ on the positive integers, a real sequence $(x_n)$ is said to be $\mathcal{I}$-statistically convergent to $\ell$ provided that $$ \textstyle \left\{n \in \mathbf{N}: \frac{1}{n}|\{k \le n: x_k \notin U\}| \ge…

Functional Analysis · Mathematics 2019-08-15 Marek Balcerzak , Paolo Leonetti

The vanishing ideal is a set of polynomials that takes zero value on the given data points. Originally proposed in computer algebra, the vanishing ideal has been recently exploited for extracting the nonlinear structures of data in many…

Machine Learning · Statistics 2018-01-30 Hiroshi Kera , Yoshihiko Hasegawa

Exactly solvable models of linear aggregation have been known since Ising's seminal one-dimensional model. This model is defined by a unique nearest-neighbour bond strength that is independent of the length of the cluster; known as…

Soft Condensed Matter · Physics 2009-11-13 J. R. Henderson

We continue the study of the rich family of norm-closed, automorphism invariant ideals of a continuous nest algebra. First we present a unified framework which captures all stable ideals as the kernels of limits of diagonal compressions. We…

Operator Algebras · Mathematics 2014-01-08 John Lindsay Orr

The elements of a finite partial order $P$ can be identified with the maximal indecomposable two-sided ideals of its incidence algebra $\A$, and then for two such ideals, $I\prec J \iff IJ \not=0$. This offers one way to recover a poset…

Combinatorics · Mathematics 2009-11-10 Rafael D. Sorkin

In addition to Pisier's counterexample of a non-accessible maximal Banach ideal, we will give a large class of maximal Banach ideals which {\it{are accessible}}. The first step is implied by the observation that a "good behaviour" of trace…

Functional Analysis · Mathematics 2016-09-06 Frank Oertel

We introduce a concept of approximately invertible elements in non-unital normed algebras which is, on one side, a natural generalization of invertibility when having approximate identities at hand, and, on the other side, it is a direct…

Functional Analysis · Mathematics 2021-06-18 Kevin Esmeral , Hans G. Feichtinger , Ondrej Hutník , Egor A. Maximenko

Trusses, defined as sets with a suitable ternary and a binary operations, connected by the distributive laws, are studied from a ring and module theory point of view. The notions of ideals and paragons in trusses are introduced and several…

Rings and Algebras · Mathematics 2019-09-25 Tomasz Brzeziński

In a previous paper, the author introduced the idea of intrinsic density --- a restriction of asymptotic density to sets whose density is invariant under computable permutation. We prove that sets with well-defined intrinsic density (and…

Logic · Mathematics 2017-09-06 Eric P. Astor

In this paper, we obtain some results on the relationships between different ideal \linebreak convergence modes namely, $\mathcal{I}^\mathcal{K}$, $\mathcal{I}^{\mathcal{K}^*}$, $\mathcal{I}$, $\mathcal{K}$, $\mathcal{I} \cup \mathcal{K}$…

General Topology · Mathematics 2021-03-05 Ankur Sharmah , Debajit Hazarika

The Turing degree spectrum of a countable structure $\mathcal{A}$ is the set of all Turing degrees of isomorphic copies of $\mathcal{A}$. The Turing degree of the isomorphism type of $\mathcal{A}$, if it exists, is the least Turing degree…

Logic · Mathematics 2007-05-23 Wesley Calvert , Valentina Harizanov , Alexandra Shlapentokh

A planar integral point set is a set of non-collinear points in plane such that for any pair of the points the Euclidean distance between the points is integral. We discuss the classification of planar integral point sets and provide…

Combinatorics · Mathematics 2021-03-30 Nikolai Avdeev , Ekaterina Momot , Aleksandr Zvolinskiy

This paper will discuss the problem of defining the new topological transitivity. To do this several equivalent topological transitive and non-wandering point has been discussed through this paper. This paper also consider the ideal version…

General Topology · Mathematics 2025-03-04 Chhapikul Miah , Shyamapada Modak

In this paper we consider nonmeasurablity with respect to sigma-ideals defined be trees. First classical example of such ideal is Marczewski ideal s_0. We will consider also ideal l_0 defined by Laver trees and m_0 defined by Miller trees.…

General Topology · Mathematics 2015-07-10 Robert Ralowski , Szymon Zeberski

Abstract upper densities are monotone and subadditive functions from the power set of positive integers into the unit real interval that generalize the upper densities used in number theory, including the upper asymptotic density, the upper…

Number Theory · Mathematics 2023-09-06 Rafał Filipów , Jacek Tryba

In this paper we examine the commutativity of ideal extensions. We introduce methods of constructing such extensions, in particular we construct a noncommutative ring T which contains a central and idempotent ideal I such that T/I is a…

Rings and Algebras · Mathematics 2013-05-15 Joachim Jelisiejew

We investigate dense lineability and spaceability of subsets of $\ell_\infty$ with a prescribed number of accumulation points. We prove that the set of all bounded sequences with exactly countably many accumulation points is densely…

Functional Analysis · Mathematics 2023-05-18 Paolo Leonetti , Tommaso Russo , Jacopo Somaglia