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In this paper we consider partial metric spaces in the sense of O'Neill. We introduce the notions of strong partial metric spaces and Cauchy functions. We prove a fixed point theorem for such spaces and functions that improves Matthews'…

General Topology · Mathematics 2015-08-18 Samer Assaf , Koushik Pal

In this article, we introduce a new type of mapping contracting perimeters of triangles in a complete metric space and present related fixed point theorem. We study the metric completeness property of the underlying space in terms of fixed…

Functional Analysis · Mathematics 2026-01-16 Tanusri Senapati

In the paper we prove generalization of Schl\"omilch's and Zetel's theorems about concurrent lines in a triangle. This generalization is obtained as a corollary of sharp geometric inequality about the ratio of triangular areas which is…

Metric Geometry · Mathematics 2025-11-07 Yagub N. Aliyev

We first introduce a notion of convex structure in generalized metric spaces, then we introduce tripartite contractions, tripartite semi-contractions, tripartite coincidence points, as well as tripartite best proximity points for a given…

General Topology · Mathematics 2019-04-24 Masoud Norouzian , Ali Abkar

The concept of quasi-partial b-metric-like spaces is being introduced and studied with the help of topology. Examples are also discussed to support the results. Some fixed point theorems are proved in the setting of quasi-partial…

General Topology · Mathematics 2018-12-04 Anuradha Gupta , Manu Rohilla

We present a complete system of inequalities for the inradius, circumradius, and diameter in the $3$-dimensional Euclidean space. To do so, we prove quasiconcavity of the inradius evaluated over $n$-simplices with a common facet…

Metric Geometry · Mathematics 2025-09-08 René Brandenberg , Bernardo González Merino , Mia Runge

In this article we establish some fixed point (known also as critical point, invariant point) theorems in quasi-metric spaces. Our results unify and further extend in some regards the fixed point theorem proposed by Dancs et al. (1983), the…

Optimization and Control · Mathematics 2015-08-11 Truong Bao , Michel Thera

It is well known that there is a strong connection between entropy inequalities and submodularity, since the entropy of a collection of random variables is a submodular function. Unifying frameworks for information inequalities arising from…

Information Theory · Computer Science 2026-01-23 Gunank Jakhar , Gowtham R. Kurri , Suryajith Chillara , Vinod M. Prabhakaran

We introduce and discuss the concept of \emph{$n$-distance}, a generalization to $n$ elements of the classical notion of distance obtained by replacing the triangle inequality with the so-called simplex inequality $$ d(x_1, \ldots,…

Metric Geometry · Mathematics 2018-05-23 Gergely Kiss , Jean-Luc Marichal , Bruno Teheux

Metric spaces are generalized by many scholars. Recently, Khatami and Mirzavaziri use a mapping called $t$-definer to popularize the triangle inequality and give a generalization of the notion of a metric, which is called a $\star$-metric.…

General Topology · Mathematics 2021-11-30 Shi-yao He , Li-Hong Xie , Peng-Fei Yan

Subject to suitable boundary conditions being imposed, sharp inequalities are obtained on integrals over a region $\Omega$ of certain special quadratic functions $f(\bf{E})$ where $\bf{E}(\bf{x})$ derives from a potential $\bf{U}(\bf{x})$.…

Analysis of PDEs · Mathematics 2014-11-14 Graeme W. Milton

Most research into similarity search in metric spaces relies upon the triangle inequality property. This property allows the space to be arranged according to relative distances to avoid searching some subspaces. We show that many common…

Information Retrieval · Computer Science 2017-03-03 Richard Connor , Franco Alberto Cardillo , Lucia Vadicamo , Fausto Rabitti

The objective of this manuscript is to introduce and develop the concept of a generalized $\theta$-parametric metric space-a novel extension that enriches the modern metric fixed point theory. We study of its fundamental properties,…

Optimization and Control · Mathematics 2025-10-02 Abhishikta Das , Hemanta Kalita , Mohammad Sajid , T. Bag

In this paper we consider a new kind of inequality related to fractional integration, motivated by Gressman's paper. Based on it we investigate its multilinear analogue inequalities. Combining with the Gressman's work on multilinear…

Functional Analysis · Mathematics 2016-06-17 Ting Chen

Gray and Kambites introduced a notion of hyperbolicity in the setting of semimetric spaces like digraphs or semigroups. We will prove that under a small additional geometric assumption their notion of hyperbolicity is preserved by…

Metric Geometry · Mathematics 2024-03-12 Matthias Hamann

In this note we prove optimal inequalities for bounded functions in terms of their deviation from their mean. These results extend and generalize some known inequalities due to Thong (2011) and Perfetti (2011)

Classical Analysis and ODEs · Mathematics 2014-03-03 Omran Kouba

In this paper we demonstrate that a well known linear inequality method developed for rational Chebyshev approximation is equivalent to the application of the bisection method used in quasiconvex optimisation. Although this correspondence…

Optimization and Control · Mathematics 2020-11-17 Vinesha Peiris , Nadezda Sukhorukova

Discrete partially ordered sets can be turned into distance spaces in several ways. The distance functions may or may not satisfy the triangle inequality, and restriction of the distance to finite chains may or may not coincide with the…

Combinatorics · Mathematics 2018-02-27 Stephan Foldes

Hayashi's Pinching Inequality, which establishes a matrix inequality between a semidefinite matrix and a multiple of its "pinched" version via a projective measurement, has found many applications in quantum information theory and beyond.…

Quantum Physics · Physics 2025-10-23 Andreas Winter

Some sharp discrete inequalities in normed linear spaces are obtained. New reverses of the generalised triangle inequality are also given.

Functional Analysis · Mathematics 2007-05-23 Sever Silvestru Dragomir