ultrametric

ultra- +‎ metric

ultrametric (not comparable)

1. (mathematics) Describing a metric whose triangle inequality has the stronger form ${\displaystyle d(x,z)\leq \max\{d(x,y),d(y,z)\}}$.
2. Describing a phylogeny in which every tip is the same distance from the root.

• metric

• p-adic ultrametric