@Article{CMR-27-4,
author = {Zhizhi, Chen and Wei, Lin and Lü-Lin, Luo},
title = {Projections, Birkhoff Orthogonality and Angles in Normed Spaces},
journal = {Communications in Mathematical Research },
year = {2011},
volume = {27},
number = {4},
pages = {378--384},
abstract = {<p style="text-align: justify;">Let $X$ be a Minkowski plane, i.e., a real two dimensional normed linear space. We use projections to give a definition of the angle $A_q(x, y)$ between
two vectors $x$ and $y$ in $X$, such that $x$ is Birkhoff orthogonal to $y$ if and only if $A_q(x, y) =&nbsp;\frac{π}{2}$. Some other properties of this angle are also discussed.</p>},
issn = {2707-8523},
doi = {https://doi.org/2011-CMR-19081},
url = {https://global-sci.com/article/81888/projections-birkhoff-orthogonality-and-angles-in-normed-spaces}
}