reserve x,y for set;

theorem Th1:
  for dl being Data-Location ex i being Nat st dl = dl.i
proof
  let dl be Data-Location;
  dl in Data-Locations SCM by AMI_2:def 16,AMI_3:27;
  then consider x,y being object such that
A1: x in {1} and
A2: y in NAT and
A3: dl = [x,y] by AMI_3:27,ZFMISC_1:84;
  reconsider k = y as Nat by A2;
  take k;
  thus thesis by A1,A3,TARSKI:def 1;
end;
