A norm $\|\raisebox{1.72218pt}{.}\|$ of a finite-dimensional vector space $V$ over $k$ is always assumed to be ultrametric, that is, $\|x+y\|\leq\max\{\|x\|,\|y\|\}$. A pair $(V,\|\raisebox{1.72218pt}{.}\|)$ is called a normed finite-dimensional vector space over $k$.