
theorem Th8:
  for T being non empty reflexive RelStr holds sigma T c= {W\
  uparrow F where W, F is Subset of T: W in sigma T & F is finite}
proof
  let T be non empty reflexive RelStr;
  let s be object;
   reconsider ss=s as set by TARSKI:1;
A1: ss\uparrow {}T = s;
  assume s in sigma T;
  hence thesis by A1;
end;
