Approximate Roberts orthogonality sets and $${(\delta, \varepsilon)}$$ ( δ , ε ) -(a, b)-isosceles-orthogonality preserving mappings

2015 ◽  
Vol 90 (3) ◽  
pp. 647-659 ◽  
Author(s):  
Ali Zamani ◽  
Mohammad Sal Moslehian
2014 ◽  
Vol 2014 ◽  
pp. 1-3 ◽  
Author(s):  
Chan He ◽  
Dan Wang

Inspired by the definition of homogeneous direction of isosceles orthogonality, we introduce the notion of almost homogeneous direction of isosceles orthogonality and show that, surprisingly, these two notions coincide. Several known characterizations of inner products are improved.


2010 ◽  
Vol 72 (3-4) ◽  
pp. 1445-1453 ◽  
Author(s):  
Jacek Chmieliński ◽  
Paweł Wójcik

Filomat ◽  
2012 ◽  
Vol 26 (4) ◽  
pp. 859-870 ◽  
Author(s):  
Eder Kikianty ◽  
Sever Dragomir

In an inner product space, two vectors are orthogonal if their inner product is zero. In a normed space, numerous notions of orthogonality have been introduced via equivalent propositions to the usual orthogonality, e.g. orthogonal vectors satisfy the Pythagorean law. In 2010, Kikianty and Dragomir [9] introduced the p-HH-norms (1 ? p < ?) on the Cartesian square of a normed space. Some notions of orthogonality have been introduced by utilizing the 2-HH-norm [10]. These notions of orthogonality are closely related to the classical Pythagorean orthogonality and Isosceles orthogonality. In this paper, a Carlsson type orthogonality in terms of the 2-HH-norm is considered, which generalizes the previous definitions. The main properties of this orthogonality are studied and some useful consequences are obtained. These consequences include characterizations of inner product space.


2020 ◽  
Vol 2020 ◽  
pp. 1-6
Author(s):  
Bhuwan Prasad Ojha ◽  
Prakash Muni Bajracharya ◽  
Vishnu Narayan Mishra

This paper generalizes the special case of the Carlsson orthogonality in terms of the 2-HH norm in real normed linear space. Dragomir and Kikianty (2010) proved in their paper that the Pythagorean orthogonality is unique in any normed linear space, and isosceles orthogonality is unique if and only if the space is strictly convex. This paper deals with the complete proof of the uniqueness of the new orthogonality through the medium of the 2-HH norm. We also proved that the Birkhoff and Robert orthogonality via the 2-HH norm are equivalent, whenever the underlying space is a real inner-product space.


2018 ◽  
Vol 6 (1) ◽  
pp. 229-236 ◽  
Author(s):  
Ljiljana Arambašic ◽  
Rajna Rajic

Abstract In this paper we present some recent results on characterizations of the Birkhoff-James and the Roberts orthogonality in C*-algebras and Hilbert C*-modules.


2013 ◽  
Vol 89 (3) ◽  
pp. 529-541 ◽  
Author(s):  
Ali Zamani ◽  
Mohammad Sal Moslehian

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