theorem Th6:
 for x being object holds <%x%> is Element of E^omega implies x in E
proof let x be object;
  assume <%x%> is Element of E^omega;
  then rng <%x%> c= E by RELAT_1:def 19;
  then {x} c= E by AFINSQ_1:33;
  hence thesis by ZFMISC_1:31;
end;
