reserve A for preIfWhileAlgebra,
  C,I,J for Element of A;
reserve S for non empty set,
  T for Subset of S,
  s for Element of S;

theorem Th79:
  for A being preIfWhileAlgebra holds A is well_founded iff
  for I being Element of A ex n being Nat st I in (ElementaryInstructions A)|^n
     by Th30;
