
 CLOSED EULERIAN PATH (Site not responding. Last check: 20071007) 
  A path is a sequence of vertices such that from each of its vertices there is an edge to the successor vertex. 
  In the example graph, (1, 2, 5, 1, 2, 3) is a path with length 5, and (5, 2, 1) is a simple path of length 2. 
  While determining whether a given graph has an Eulerian path or cycle is trivial, solving the same problem for Hamiltonian paths and cycles appears to be extremely hard. 
 www.webstersonlinedictionary.org /definition/CLOSED+EULERIAN+PATH (1234 words) 
