Type: Article
Publication Date: 2007-01-01
Citations: 48
DOI: https://doi.org/10.7153/mia-10-43
We shall present a sharp triangle inequality and its reverse inequality with n elements in a Banach space X , or equivalently we shall estimate the difference n j=1 x j -n j=1 x j for given x 1 , x 2 , . . ., x n in X , where equality attainedness will be characterized.Several applications will be given.