arango> db.relation.outEdges("vertex/1528086");
[
  {
    "_id" : "relation/3100950",
    "_key" : "3100950",
    "_rev" : "3100950",
    "_from" : "vertex/1528086",
    "_to" : "vertex/1593622",
    "label" : "knows"
  }
]
arango> db.relation.outEdges("vertex/1593622");
[ ]