Huh. That is a good point. In Gremlin you can chain steps together (e.g. out("knows").out("mother").out("worksFor")) and you can match patterns. So, to be clearer, I should have represented the chain as a one-liner or as a two liner with an indent.

  out("knows").aggregate("friends").out("knows").where(not(within("friends")))

OR

  out("knows").aggregate("friends").
    out("knows").where(not(within("friends")))

Note the "." concatenation that ties the two lines together into a chain. When nesting parallel traversals (e.g. match()), the traversal patterns are delineated by ",".

  . = AND
  , = OR

Ha. Thats a generally neat way to think of "." and "," in computing. mult and + ...the algebra.

FYI in SPARQL

  SELECT ?foaf
  WHERE 
  {
    ?me a <USER> .
    ?me <KNOWS> ?friend . ?friend <KNOWS> ?foaf .
    MINUS {:me <KNOWS> ?foaf }
  }

OR

  SELECT ?foaf
  WHERE 
  {
    ?me a <USER> .
    ?me <KNOWS>/<KNOWS> ?foaf .
    MINUS {:me <KNOWS> ?foaf }
  }