title: Gremlin: need an efficient query to check whether two vertices are connected?
body: <p>Our app needs to check whether two vertices are connected via any path.</p>
  
  <p>The app does not care about the segments in a path, or the shortest path.  </p>
  
  <p>The app only needs to know if two vertices share a common sub-graph.</p>
  
  <p><strong>My question:</strong> given two vertices with id(s) A and B, respectively, what gremlin query works well to answer the question "are A and B connected, somehow?"</p>