theorem
  u [= FinMeet(B,f) implies for x st x in B holds u [= f.x
proof
  assume
A1: u [= FinMeet(B,f);
  let x;
  assume x in B;
  then FinMeet(B,f) [= f.x by Th40;
  hence thesis by A1,LATTICES:7;
end;
