@MISC{RLSUB_2.MIZ,
  AUTHOR = {Trybulec, Wojciech A.},
  TITLE = {Operations on Subspaces in Real Linear Space},
  DAY = {20},
  MONTH = {September},
  YEAR = {1989},
  ADDRESS1 = {Warsaw University},
  SUMMARY = {In this article the following operations on subspaces of real linear space
are intoduced: sum, intersection and direct sum. Some theorems about those
notions are proved. We define linear complement of a subspace.
Some theorems about decomposition of a vector onto two subspaces
and onto subspace and its linear complement are proved.
We also show that a set of subspaces with operations sum and intersection
is a lattice.
At the end of the article theorems that belong rather to \cite{BOOLE.ABS},
 \cite{RLVECT_1.ABS}, \cite{RLSUB_1.ABS} or \cite{LATTICES.ABS} are proved.}}

