Inequalities for curvature integrals in Euclidean plane

Abstract Let γ be a closed strictly convex curve in the Euclidean plane R2 $\mathbb{R}^{2}$ with length L and enclosing an area A, and A˜1 $\tilde{A}_{1}$ denote the oriented area of the domain enclosed by the locus of curvature centers of γ. Pan and Xu conjectured that there exists a best constant...

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Main Author: Zengle Zhang
Format: Article
Language:English
Published: SpringerOpen 2019-06-01
Series:Journal of Inequalities and Applications
Subjects:
Online Access:http://link.springer.com/article/10.1186/s13660-019-2116-5
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author Zengle Zhang
author_facet Zengle Zhang
author_sort Zengle Zhang
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description Abstract Let γ be a closed strictly convex curve in the Euclidean plane R2 $\mathbb{R}^{2}$ with length L and enclosing an area A, and A˜1 $\tilde{A}_{1}$ denote the oriented area of the domain enclosed by the locus of curvature centers of γ. Pan and Xu conjectured that there exists a best constant C such that L2−4πA≤C|A˜1|, $$\begin{aligned} L^{2}-4\pi A\leq C \vert \tilde{A}_{1} \vert , \end{aligned}$$ with equality if and only if γ is a circle. In this paper, we give an affirmative answer to this question. Moreover, instead of working with the domain enclosed by the locus of curvature centers we consider the domain enclosed by the locus of width centers of γ, and we obtain some new reverse isoperimetric inequalities.
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spelling doaj.art-7ac1eb012d6d429484a97ebf8eb0818b2022-12-22T01:26:37ZengSpringerOpenJournal of Inequalities and Applications1029-242X2019-06-012019111210.1186/s13660-019-2116-5Inequalities for curvature integrals in Euclidean planeZengle Zhang0School of Mathematics and Finance, Chongqing University of Arts and SciencesAbstract Let γ be a closed strictly convex curve in the Euclidean plane R2 $\mathbb{R}^{2}$ with length L and enclosing an area A, and A˜1 $\tilde{A}_{1}$ denote the oriented area of the domain enclosed by the locus of curvature centers of γ. Pan and Xu conjectured that there exists a best constant C such that L2−4πA≤C|A˜1|, $$\begin{aligned} L^{2}-4\pi A\leq C \vert \tilde{A}_{1} \vert , \end{aligned}$$ with equality if and only if γ is a circle. In this paper, we give an affirmative answer to this question. Moreover, instead of working with the domain enclosed by the locus of curvature centers we consider the domain enclosed by the locus of width centers of γ, and we obtain some new reverse isoperimetric inequalities.http://link.springer.com/article/10.1186/s13660-019-2116-5CurvatureReverse isoperimetric inequalityOriented areaWidth function
spellingShingle Zengle Zhang
Inequalities for curvature integrals in Euclidean plane
Journal of Inequalities and Applications
Curvature
Reverse isoperimetric inequality
Oriented area
Width function
title Inequalities for curvature integrals in Euclidean plane
title_full Inequalities for curvature integrals in Euclidean plane
title_fullStr Inequalities for curvature integrals in Euclidean plane
title_full_unstemmed Inequalities for curvature integrals in Euclidean plane
title_short Inequalities for curvature integrals in Euclidean plane
title_sort inequalities for curvature integrals in euclidean plane
topic Curvature
Reverse isoperimetric inequality
Oriented area
Width function
url http://link.springer.com/article/10.1186/s13660-019-2116-5
work_keys_str_mv AT zenglezhang inequalitiesforcurvatureintegralsineuclideanplane