reserve p, q for FinSequence,
  e,X for set,
  i, j, k, m, n for Nat,
  G for Graph;
reserve x,y,v,v1,v2,v3,v4 for Element of G;
reserve vs, vs1, vs2 for FinSequence of the carrier of G,
  c, c1, c2 for oriented Chain of G;
reserve sc for oriented simple Chain of G;
reserve x,y for set;

theorem
  for c1 being FinSequence holds (c1 is Simple oriented Chain of G iff
  c1 is oriented simple Chain of G)
  &(c1 is oriented simple Chain of G implies c1 is OrientedPath of G)
  by Th18,Th19,Th23;
