x1 is direct ancestor/mentorial-ancestor of x2 of order x3 (li; nonnegative integer) in graph/network of ancestry (family tree) x4 (defaults to maximal option), where x3 is the smallest possible number which is so constrained; x1 is the x3th-great-grandparent of x2.
If x3=0, then x1 = x2; if x3=1, then x1 is the parent/mentor/rirni x2; if x3=2, then x1 is the grandparent/mentor's mentor/riryrirni of x2; if x3=n, then x1 is the (n-2)th-great-grand-parent of x2 (id est: great-great-...-great-grandparent, where the number of "great-"s is n-2). x3 must be the geodesic path length; in an actual tree-graph family tree, this is the only option; but, in practice, there is usually some closure of the graph (inbreeding/incest) and one specimen may be the ancestor of the subject in multiple different ways; in such cases, the shortest path(s) are the ones which determine x3 and, thus, x4 can be used to subtract out those connections in order to say something like "A is both B's grandparent and B's great-grandparent" (the latter requiring edge-subtraction from the ancestry graph). See also: ".utka'au", "rirni", ".abvele", riryriryrirni.