theorem Th9:
  ic in rng p & ( ic = b := (fa, a) or ic = (fa, a) := b)
  implies fa in UsedI*Loc p
proof
  assume that
A1: ic in rng p and
A2: ic = b := (fa, a) or ic = (fa, a) := b;
A3: UsedInt*Loc ic = {fa} by A2,SF_MASTR:33;
  UsedInt*Loc ic c= UsedI*Loc p by A1,SF_MASTR:35;
  hence thesis by A3,ZFMISC_1:31;
end;
