Euclidean Metric is a Metric
From ProofWiki
Theorem
The Euclidean metric is a metric.
Proof
This is a special case of the generalized Euclidean metric which is proved to be a metric here.
$\blacksquare$
Sources
- W.A. Sutherland: Introduction to Metric and Topological Spaces (1975): Example $2.2.1$