# Distance Value

A Distance Value is a Non-Negative Real Number Output for the Distance Function (between two Things in a Metric Space).

**Context:**- It must be Zero when the two items are identical.
- It must be constrained by the Triangle Inequality).
- It must be a Positive Number if the two things are not the same things, because 2*Dist(x,y) = Dist(x,y) + Dist(y,x) ≥ Dist(x,x) = 0.
- It can be a Natural Number (for example for the L1 Norm Distance Function - city block distance).

**Example(s):**- 5 <- L2(3,4).
- Vector Distance Value.

**See:**Similarity Score.