- w(min) = 0
- w(max) = 1
- If x > y, then w(x) > w(y)
- let z = join(x,y). Then w(x) + w(y) >= w(z)
w(x) + w(y) >= w(z) + w(u) (where u = meet(x,y)).
My question is: is there a well known name for such a weight function ? I've been trying to search various sources, and the closest I came to this was the notion of a 'rank' function for a lattice, which doesn't quite capture this sort-of-metric-property.