We can use the variants of path processing to determine multi-generational family relationships
The data for this query can be downloaded at Family.ttl and FamiltyRules.ttl
Query ch6.34 Joe's children 
We start with direct children of the patriarch
Query ch6.35 Joe's grandchildren
We can do two generations directly as well
Query ch6.36 Joe and his descendant
We can do any number of generations using a Kleene star.
Query ch6.37 Joe's Descendants
A plus sign leaves out zero matches.