reserve x,y,z for set;
reserve f,f1,f2,f3 for FinSequence,
  p,p1,p2,p3 for set,
  i,k for Nat;
reserve D for non empty set,
  p,p1,p2,p3 for Element of D,
  f,f1,f2 for FinSequence of D;
reserve D for non empty set;

theorem Th114:
  for i being Nat, f being FinSequence st
    1<=i & i<=len f holds (Rev f).i=f.(len f -i+1)
proof
  let i be Nat,f be FinSequence;
  assume that
A1: 1<=i and
A2: i<=len f;
  i in dom (f) by A1,A2,FINSEQ_3:25;
  hence thesis by FINSEQ_5:58;
end;
