
theorem
  for V being RealUnitarySpace, w1,w2,w3 being VECTOR of V holds w1 in
  Lin{w1,w2,w3} & w2 in Lin{w1,w2,w3} & w3 in Lin{w1,w2,w3}
proof
  let V be RealUnitarySpace;
  let w1,w2,w3 be VECTOR of V;
A1: w3 in {w1,w2,w3} by ENUMSET1:def 1;
  w1 in {w1,w2,w3} & w2 in {w1,w2,w3} by ENUMSET1:def 1;
  hence thesis by A1,Th2;
end;
