
theorem
  for V being RealUnitarySpace, W being Subspace of V, L being
Linear_Compl of W, v being VECTOR of V holds (v |-- (W,L))`1 + (v |-- (W,L))`2
  = v
proof
  let V be RealUnitarySpace, W be Subspace of V, L be Linear_Compl of W;
  V is_the_direct_sum_of W,L by Th35;
  hence thesis by Def6;
end;
