Strictly convex abelian metric groups are normed spaces
https://doi.org/10.15330/cmp.18.1.198-210
Keywords:
strictly convex metric space, normed space, abelian metric group, geodesic metric space, finite-dimensional normed space, locally compact metric group, $\mathbb R$-normable metric groupAbstract
We prove that every strictly convex abelian metric group has a canonical structure of a normed space over the field of real numbers. We deduce this fact from the $\mathbb R$-normability of strictly convex metric groups. Moreover, we prove that a strictly convex (more generaly, $\mathbb R$-normable) metric group is a finite-dimensional normed space if and only if it is locally compact if and only if it is (compactly) finite-dimensional. Also we prove that every strictly convex metric space is geodesic.