scholarly journals On finding the exact values of the constant in a $(1,q)$-generalized triangle inequality for Box-quasimetrics on 2-step Carnot groups with 1-dimensional center

2021 ◽  
Vol 18 (2) ◽  
pp. 1251-1260
Author(s):  
A. V. Greshnov
2005 ◽  
Vol 2005 (18) ◽  
pp. 2883-2893 ◽  
Author(s):  
A. H. Ansari ◽  
M. S. Moslehian

Refining some results of Dragomir, several new reverses of the generalized triangle inequality in inner product spaces are given. Among several results, we establish some reverses for the Schwarz inequality. In particular, it is proved that ifais a unit vector in a real or complex inner product space(H;〈.,.〉),r,s>0,p∈(0,s],D={x∈H,‖rx−sa‖≤p},x1,x2∈D−{0}, andαr,s=min{(r2‖xk‖2−p2+s2)/2rs‖xk‖:1≤k≤2}, then(‖x1‖‖x2‖−Re〈x1,x2〉)/(‖x1‖+‖x2‖)2≤αr,s.


2012 ◽  
Vol 75 (2) ◽  
pp. 735-741 ◽  
Author(s):  
Farzad Dadipour ◽  
Mohammad Sal Moslehian ◽  
John M. Rassias ◽  
Sin-Ei Takahasi

2014 ◽  
Vol 12 (11) ◽  
Author(s):  
Tamotsu Izumida ◽  
Ken-Ichi Mitani ◽  
Kichi-Suke Saito

AbstractIn this paper, we consider a generalized triangle inequality of the following type: $$\left\| {x_1 + \cdots + x_n } \right\|^p \leqslant \frac{{\left\| {x_1 } \right\|^p }} {{\mu _1 }} + \cdots + \frac{{\left\| {x_2 } \right\|^p }} {{\mu _n }}\left( {for all x_1 , \ldots ,x_n \in X} \right),$$ where (X, ‖·‖) is a normed space, (µ1, ..., µn) ∈ ℝn and p > 0. By using ψ-direct sums of Banach spaces, we present another approach to characterizations of the above inequality which is given by [Dadipour F., Moslehian M.S., Rassias J.M., Takahasi S.-E., Nonlinear Anal., 2012, 75(2), 735–741].


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