The distance in Z12

Let a,b∈ Z12 be two distinct elements, then the distance of a and b is 1 if and only if the interval b-a is 1 or 11. The distance is 2 if the interval b-a is 2 or 10. The distance is 3 if the interval b-a is 3 or 9. The distance is 4 if the interval b-a is 4 or 8. The distance is 5 if the interval b-a is 5 or 7. The distance is 6 if the interval b-a is 6.
interval distance
0 0
1, 11 1
2, 10 2
3, 9 3
4, 8 4
5, 7 5
6 6

Database on tone rows and tropes
harald.fripertinger "at" uni-graz.at
January 2, 2019