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;

theorem Th61:
  p in rng(f:-p)
proof
  rng<*p*> = {p} by FINSEQ_1:39;
  then
A1: p in rng<*p*> by TARSKI:def 1;
  f:-p = <*p*>^(f/^p..f) by FINSEQ_5:def 2;
  then rng(f:-p) = rng<*p*> \/ rng(f/^p..f) by FINSEQ_1:31;
  hence thesis by A1,XBOOLE_0:def 3;
end;
