Is the absolute value function a metric? I was trying to find out more information about absolute value, and I came upon the fact that AV satisfies a whole set of properties that usually defines a distance function or metric. But in the Wikipedia article on metrics, there's no mention of the AV function, so I'm a bit confused now. Is it some sort of metric subspace instead?
P.S.: I'm not at all well-versed on metrics, so I'd appreciate simple answers :)

No,the absolute value function $|\cdot|:\mathbb R\to[0,\infty)$ is not a metric.
A metric on a set $X$ is a function $d:X\times X\to[0,\infty)$ defined on the cartesian square of the set $X$ satisfying certain properties, and the absolute value function is not of that form.
What it is true is that out of the absolute value you can construct a metric: indeed, the function $$(x,y)\in\mathbb R\times\mathbb R\longmapsto|x-y|\in[0,\infty)$$ is a metric.
