Metric
= Metric
{title2=$d$}
{wiki=Metric_(mathematics)}
A metric on a <set> $X$ is a function $d:X\times X\to[0,\infty)$ that is symmetric, satisfies the <triangle inequality>, and obeys $d(x,y)=0$ exactly when $x=y$.
= Metric
{title2=$d$}
{wiki=Metric_(mathematics)}
A metric on a <set> $X$ is a function $d:X\times X\to[0,\infty)$ that is symmetric, satisfies the <triangle inequality>, and obeys $d(x,y)=0$ exactly when $x=y$.