reserve s for State of SCM+FSA,
  a, c for read-write Int-Location,
  aa, bb, cc,
  dd, x for Int-Location,
  f for FinSeq-Location,
  I, J for MacroInstruction of SCM+FSA,
  Ig for good MacroInstruction of SCM+FSA,
  i, k for Nat,
  p for Instruction-Sequence of SCM+FSA;

theorem Th7:
 for I,J being really-closed MacroInstruction of SCM+FSA holds
  cc <> aa & I does not destroy cc & J does not destroy cc implies
  if>0(aa, bb, I, J) does not destroy cc
proof let I,J be really-closed MacroInstruction of SCM+FSA;
  assume that
A1: cc <> aa and
A2: I does not destroy cc & J does not destroy cc;
  if>0(aa, bb, I, J) = SubFrom(aa,bb) ";" if>0(aa,I,J) &
   if>0(aa,I,J) does not destroy cc by A2,SCMFSA8B:def 5,SCMFSA8C:88;
  hence thesis by A1,SCMFSA7B:8,SCMFSA8C:53;
end;
