anchor.diff:    select(keys).limit(1)
   ----
   
  -<1> The main difference for OLAP is the use of `aggregate()` over the mid-traversal`V()`.
  +<1> The main difference for OLAP is the use of `aggregate()` over the mid-traversal `V()`.
   
   === Maximum Depth
   
  
positive.code: those without incoming edges). Second, all results save the last one can be ignored to that point (i.e. the last one is
  the one at the deepest point in the tree). In this way, the path and path length only need to be calculated for a
  single result.
  
  === Time-based Indexing
  
  
negative.code: ----
  
  image:gremlin-max-depth.png[float=right,width=350]The traversals shown above are fairly straightforward. The traversal
  beings at a particular starting vertex, traverse in on the "hasParent" edges emitting all vertices as it goes. It
  calculates the path length and then selects the longest one. While this approach is quite direct, there is room for
  improvement:
  
  