Distance

Properties of distance

Let $d(x,y)$ be our distance function. Then,

1. $d(\cdot ,\cdot )\ge 0$
2. $d(p,p)=0$
3. $d(\theta ,p)=d(p,\theta )$
4. $d(p,q)\le d(p,r)+d(r,q)$

Some distance measures

1. Euclidean Distance
2. Mahalanobis Distance