reserve a, b, c, a1, a2, b1, b2 for Int-Location,
  l, l1, l2 for Nat,
  f, g, f1, f2 for FinSeq-Location,
  i, j for Instruction of SCM+FSA,
  X, Y for set;

theorem Th14:
  i = a:=b or i = AddTo(a, b) or i = SubFrom(a, b) or i = MultBy(a
  , b) or i = Divide(a, b) implies UsedIntLoc i = {a, b}
proof
  reconsider ab = {a, b} as Element of Fin Int-Locations
     by FINSUB_1:def 5;
  assume
A1: i = a:=b or i = AddTo(a, b) or i = SubFrom(a, b) or i = MultBy(a, b)
  or i = Divide(a, b);
  then InsCode i = 1 or ... or InsCode i = 5 by SCMFSA_2:18,19,20,21,22;
  then InsCode i in {1, 2, 3, 4, 5} by ENUMSET1:def 3;
  then UsedIntLoc i = ab by A1,Def1;
  hence thesis;
end;
