theorem Th50:
  for dl being FinSeq-Location holds dl <> IC SCM+FSA
proof
  let dl be FinSeq-Location;
 now assume NAT in INT \ NAT;
  then
A1: NAT in NAT \/ [:{0},NAT:] by NUMBERS:def 4,XBOOLE_0:def 5;
 per cases by A1,XBOOLE_0:def 3;
 suppose NAT in NAT;
 hence contradiction;
 end;
 suppose NAT in [:{0},NAT:];
 hence contradiction by FINSET_1:15;
 end;
 end;
 hence thesis by Def3,Th1;
end;
