theorem Th20:
 for S be IC-Ins-separated non empty
 with_non-empty_values Mem-Struct over N, l be Nat
  holds DataPart Start-At(l,S) = {}
proof
 let S be IC-Ins-separated non empty
 with_non-empty_values Mem-Struct over N, l be Nat;
  Data-Locations S misses {IC S} by XBOOLE_1:79;
  then Data-Locations S misses dom Start-At(l,S);
 hence thesis by RELAT_1:66;
end;
