tursei lujvo

x1 is x3 (undirected) hops away from x2 in graph x4

Note the switched x2 and x3. Distributive across all four arguments. See stura, nenri, grafu, tcana, dzena, turne'i, turnela, turnersei, turtuba. No in-language definition for now because of uncertainty about grafu's definition.

In notes:

turne'i
x1 is a descendant of x2 in hierarchy x3
turnela
x1 is a child of x2 (one level below it) in hierarchy x3
turnersei
x1 is a descendant of x2, x3 levels down from it, in hierarchy x4
turtuba
x1 and x2 share common parent x3 in hierarchy x4